Brené Brown, PhD, LMSW, author of The Gifts of Imperfection and research professor at the University of Houston, has spent the last 12 years figuring out what keeps us from the living—despite our best efforts—the kind of wholehearted, fully involved existences that we're trying to lead. It turns out that a lot of the assumptions we hold so dear and we believe will turn around everything are...well...just plain wrong.

1. Fitting In Is Not Belonging

There are so many terms we use every day whose meanings are gauzy, if not downright imprecise—which makes it hard to get your head around what's really going on in your life. For example, contrary to what most of us think: Belonging is not fitting in. In fact, fitting in is the greatest barrier to belonging. Fitting in, I've discovered during the past decade of research, is assessing situations and groups of people, then twisting yourself into a human pretzel in order to get them to let you hang out with them. Belonging is something else entirely—it's showing up and letting yourself be seen and known as you really are—love of gourd painting, intense fear of public speaking and all.

Many us suffer from this split between who we are and who we present to the world in order to be accepted, (Take it from me: I'm an expert fitter-inner!) But we're not letting ourselves be known, and this kind of incongruent living is soul-sucking.

In my research, I've interviewed a lot of people who never fit in, who are what you might call "different": scientists, artists, thinkers. And if you drop down deep into their work and who they are, there is a tremendous amount of self-acceptance. Some of them have to scrap for it, like the rest of us, but most are like this neurophysicist I met who, essentially, told me, "My parents didn't care that I wasn't on the football team, and my parents didn't care that I was awkward and geeky. I was in a group of kids at school who translated books into the Klingon language. And my parents were like, ‘Awesome!' They took me to the Star Trek convention!" He got his sense of belonging from his parents' sense of belonging, and even if we don't get that from Mom and Dad, we have to create it for ourselves as adults—or we will always feel as if we're standing outside of the big human party.

The truth is: Belonging starts with self-acceptance. Your level of belonging, in fact, can never be greater than your level of self-acceptance, because believing that you're enough is what gives you the courage to be authentic, vulnerable and imperfect. When we don't have that, we shape-shift and turn into chameleons; we hustle for the worthiness we already possess.

2. Guilt Is Not Bad for You

I'm just going to say it: I'm pro-guilt. Guilt is good. Guilt helps us stay on track because it's about our behavior. It occurs when we compare something we've done—or failed to do—with our personal values. The discomfort that results often motivates real change, amends and self-reflection.

I interview people of just about every faith you can imagine, and a lot of them will say, "Oh, I've got major Catholic guilt" or "I've got major Jewish guilt." And I'll say, "Tell me about it." And they'll say, "Well, if I don't show up for Shabbat every Friday, I'm a bad son. My brother always goes."

Clinically speaking, that's not guilt. That's shame, and one of the worst things about shame is that we often don't know when we're feeling it. When I'm interviewing subjects, I hear, "I'm worthless. I'm a piece of crap. I don't blame my parents for hating me—who wouldn't?" And this is shame. We may not know how to name it. But we know how to feel it—and it is a totally separate emotion from guilt

A clear way to see the difference is to think about this question: If you made a mistake that really hurt someone's feelings, would you be willing to say, "I'm sorry. I made a mistake"? If you're experiencing guilt, the answer is yes: "I made a mistake." Shame, on the other hand, is "I'm sorry. I am a mistake." Shame doesn't just sound different than guilt; it feels different. Once we understand this distinction, guilt can even make us feel more positively about ourselves, because it points to the gap between what we did and who we are—and, thankfully, we can change what we do.

3. Perfectionism Is Not About Striving for Excellence

For some of us (including me), what I'm about to say is horrifying: Perfectionism is not about achievement and growth. Perfectionism is the belief that if we live perfectly, look perfectly and act perfectly, we can avoid the pain of blame, judgment and shame.

Most perfectionists (also including me) grew up being praised for achievement and performance in our grades, manners and appearance. Somewhere along the way, we adopted this dangerous and debilitating belief system: I am what I accomplish and how well I accomplish it. A ticker tape began to stream through our heads: Please. Perform. Perfect.

Healthy striving, meanwhile, focuses on you. It occurs when you ask yourself, "How can I improve?" Perfectionism keeps the focus on others. It occurs when you ask, "What will they think?" Research, unfortunately, shows that perfectionism hampers success and often leads to depression, anxiety, addiction and missed opportunities, due to fears of putting anything out in the world that could be imperfect or disappoint others. It's a 20-ton shield that we lug around thinking it will protect us when, in fact, it's the thing that's really preventing us from taking flight. Another way to think about it? Consider Leonard Cohen's song "Anthem," which says, "There's a crack in everything. That's how the light gets in."

4. Vulnerability Is an Act of Courage

There are a few myths about vulnerability that I think keep us from being wholehearted people who can fully give and receive love. The first is that vulnerability is weakness. The second is that it's optional.

First of all, vulnerability is not weakness. It's probably the most accurate measure of our individual courage. When I ask research subjects to give me an example of being in situations where they feel vulnerable, they say, "Taking responsibility for something that went wrong at work" or "Telling my boyfriend that I love him" or "Calling my friend whose child just died" or "Sending my kid to school knowing she is struggling but knowing she had has to figure it out" or "Meeting with the hospice person who is going to be taking care of my mother."

Sometimes I hear people say "I don't do vulnerability." But you do it, everyday. We all do it. We all have those moments. The only choice you have is how you handle those feelings of being terrifyingly, painfully exposed. Maybe you turn them into rage; maybe you turn them into disconnection; maybe you numb them; maybe you turn them into perfectionism (which, by the way, is what I do with them). But you do something with them.

The key to transforming them into courage instead is learning how recognize them, feel them and ultimately make the choice to simply be there, with that horrible tangle of uncertainty and risk. When you know what you're feeling and why, you can slow down, breathe, pray, ask for support—and make choices that reflect who you are and what you believe.