Before taking up yoga, be forewarned: the practice will inspire you to a greater level authenticity in many of your personal relationships.

This includes your connection with others and your biggest, bestest, baddest BFF ever — yourself. Weird things will happen.

Caveat emptor!

If you’re like oh so many ladies in our great world (myself included), you’ve been socialized to be ‘nice.’ While ‘niceness’ can mean different things to different people, social ‘niceness’ always includes the suppression of feelings like irritation, anger or betrayal. ‘Niceness’ often contains a vague element of manipulation or one ‘upsmanship.’

Being ‘nice,’ however, is not the same as displaying courage, integrity or character. Our culture conditions women to ‘put on a happy face’ during times of turmoil. It assures us that ‘the sun will come out tomorrow.’

On the other hand, it encourages men to beat the sh*t out of each other. While I do not advocate gratuitous violence, I do think a quick fist to the jawbone causes stress hormones to abate quickly. This, in my book, gains at least a few points for authenticity.

I love to observe ‘niceness’ in action on the new TV series Revenge. While the guys duke it out, the women choreograph their displeasure with smiles and nods. They might just as easily be throwing ninja stars or daggers.

The recent movie, Bridesmaids, chronicles the hilarious exploits of Kristin Wiig’s character. A friend’s impending wedding serves as a catalyst for a war with a co-bridesmaid who seems dementedly, psychotically perfect. When Wiig succumbs to a violent case of food poisoning at a dress fitting, her arch nemesis attempts to unseat her. Wiig, nauseous and covered in sweat, unsuccessfully chats and coos. We all know the subtext. We’ve all been there, in one way or another.

What would the world be like if we said exactly what we meant, well, more or less?

Fellow yoginis, let’s examine the toll all this ‘niceness’ extracts from bodies after weeks, months, years, perhaps a lifetime, of being nice: the stress, the tension, the stiffness. Then we tell ourselves we shouldn’t feel it, making things even worse. Hogwash!

Your smart body is trying to tell you something that your stupid mind should be aware of — if it weren’t for all of this cultural gobbledygook about being nice.

Like a consistent yoga practice, good friends help us to be healthy, wealthy and wise, physically, emotionally and spiritually.

We, in turn, hope we can be a part of their journey towards clarity. It is difficult to imagine Thelma without Louise. Calvin without Hobbes. Huckleberry Finn without Jim.

On the long raft trip of life, one thing is inevitable: adversity. At some point, we will all find ourselves pursued by weapon-toting hooligans, out-of-control steamboats and venomous snakes. To accomplish great things, we must know that somebody has our backs covered and vice versa.

Being too ‘nice’ can wreck a friendship faster than you can say, “Paris Hilton and Nicole Ritchie,” or “Monica Lewinsky and Linda Tripp.”

Do you have a hunch that a favorite friend has been behaving badly? Do you believe that being ‘yogic’ means putting on a smile — never calling people on their shit?

Has your energy field become as heavy and cumbersome as your microfiber towel after a particularly energetic Bikram sesh? Are you reluctant to admit how ‘nice’ is underserving your own self?

Call a spade a spade and acknowledge it already! Do you feel a pit in your stomach when a certain friend’s name appears on your caller ID? Do your shoulders tense as you drive to meet her for coffee? Do your hips cramp when you see her on Facebook chat? Does your energy field wilt and deplete from spending time with a certain person or group of people? Your limbic system — the smartest part of the body — is telling you to get out of Dodge!

As much as humanly possible, you should heed this advice. Who do you think you’re kidding? Your reptilian brain knows yourself better than you do, Grasshopper. Think how your body feels in the presence of kind and courageous company: relaxed, limber, expansive to the possibilities of the universe. For God’s sake (and for your own), please maximize time spent with this type of person.

Having a few good friends (and I don’t mean 1,000 plus Facebook friends) is important in today’s fast-paced world. As young people delay marriage and move far from family for work or educational reasons, we find ourselves relying more heavily on female friends than women of generations past. We talk. We have coffee or lunch. We dish about really creepy dates or bad jobs. Think of the popularity of shows featuring platonic pals, like Sex and the City.

Friends become one’s surrogate family.

Sometimes, the situation is less cut-and-dry. Enter an example from my own life. I often have friends who meet a new guy and disappear from existence. You give it a few weeks, then a few months. Oh well, your friend is in love, you tell yourself.

Then, you start to worry: Your BFF is completely MIA. True, sometimes friendships end for natural reasons. Someone decides to get a Ph.D in quantum physics. Someone marries her lab partner. Someone leaves for a testing site in the deserts of Arizona, never to return. But something here seems suspect.

Nice jumps into the driver’s seat. You turn things on yourself. You worry: What did I do?

Cell messages, texts, carrier pigeons and smoke signals are unanswered. Should you count your friendship as DOA? Is she in love and should you just forget she ever existed for Wednesday night game night or Thursday happy hour? I’m not really jealous, just feeling a little confused.

In all honesty, you realize this has happened many times before with many different friends. You have chosen to overlook it. You want her to be happy, but you employ a wide variety of mental calisthenics to make yourself shut the hell up about it.

When you are dating someone, you strive to stay in touch with good pals, to let them know you’re still there. You anticipate the best: Maybe she was abducted by aliens and taken to the planet Rador. You prepare for the worst: maybe you are just a horrible friend! Nobody will ever like you.

Eventually, you give up. Then, almost inevitably, the universe answers your question in the form of a sad, late night call from her. Before you can express your concern that she was abducted or your own personal woes — you were laid off from your job and living in a van at the local park — she blurts out: “Jim (or Bob, or Kevin or Rich) and I just broke up. I don’t know who else to call!”

Of course she doesn’t.

That thought lingers at the back of your mind: you’re being a doormat. You’re being gullible. In all honesty, I admitted that this kind of thing had happened many times before. You enable this behavior by continuing with the charade. You ignore the little voice inside. You assure her of her many positive qualities — because that’s what ladies do for each other.

You agree to meet for lunch the next day. You discuss the break-up and not much else. Inevitably, a new guy will come into the picture. She pulls a Houdini. And you begin to feel like the magician’s assistant who lies in the secret box, is driven through with swords, and emerges unscathed.

Trust me on this. Better yet, trust your body on this. If there is a five alarm siren screeching, it should be doing so now. Maybe it looks more like Jacob Marley’s chalk-stained face, moaning and shaking chains in A Christmas Carol? Whichever seems more appropriate.

Around New Year’s, I decided to use my yoga practice as a tool to take a powerful inside look.

I was in my early 30s and had this happened many, many times. While I could not change the situation, I could give a long hard look at my associates. How was I not being authentic to myself? I didn’t want to whine. I’m not really a jealous person. In the immortal words of Road Rules, I wanted to stop being polite and start getting real. If it was time to venture into that dark and dastardly forest, now was probably a danged good time. My shadow self was longing to talk. I reckoned it would have plenty to say.

I took an afternoon jog to psych myself up. That evening, I did a yoga practice featuring a lot of heart-openers and twists. I did Upward-Facing Dog to open the front of the body, Pigeon Pose to free up residual anger in the hips, Viparita Karani to bring fresh blood to my digestive system.

I would begin to notice a dull ache, like being stabbed in my back, behind the heart area. While I’d always believed in this mind-over-matter stuff, I’d never really been one to take it to the streets, share too much with strangers. I didn’t want people to think I was weird, like that creepy lady in the drugstore who is always passing out business cards and offering to examine my aura. I was intrigued. I practiced a few heart-opening meditations. I imagined the earth drawing out the negative energy from behind my heart, the habituations of Samskara. I went to sleep.

I awakened in the middle of the night to find that the place behind my heart was now very warm and soft. It felt like an object had become lodged in there. My mouth tasted a little something like blood, and it wasn’t that CSI episode I watched earlier in the evening.

I felt very connected to something, like something was about to change.

Was this what transparency was about? Is this the culmination of all this damned yoga stuff about being authentic and vulnerable? Do you get a freaking knife stabbed into your back?

No, yoga allows you to make the bloody realization that there is a knife in your back. And you may have been complicit in allowing it to remain there.

Niceness is really a little like ignorance.

The universe was speaking to me. Like one of those medieval movies with a sword being lodged in a stone, I was being implored to pull it out.

But, what did that voice sound like? Was it loud and booming? someone asked.

Not exactly. But it was firm and very commanding.

Continue repeating this pattern, it said, and you will never move again. Can you give it up?

Yes, I promise, I said. Like a sword suddenly extracted from its scabbard and it was gone.

What is the moral of the story? Don’t take crap standing up. I don’t mean you should whack your friend. (After all, you’ve probably contributed to her behavior by not standing up for yourself).

Get to your mat, and do some heart openers and see where life takes you. Stay strong. Stay tuned in. Don’t just sit there and, for the sake of all that is good and holy, don’t just be ‘nice.’