And we wonder why...

I just need to rant.
Ever wonder why almost everyone in America is so miserable? Maybe its because we learn to talk, but never learn to honestly communicate.
For instance: would someone PLEASE tell me how to talk to a mother? They want you to be honest with them, but they criticize what you say. I know they want to protect you from making stupid decisions or whatever, and I understand and respect that, but for crying out loud. I've gotten to the point that I don't want to make decisions anymore because I feel like my mother will criticize it...no matter what I choose!
I'm seriously about to lose it. And when I do, I'm afraid I'll lose the relationship with my mother. I feel like I'm going to seriously bite her head off. Don't get me wrong. I love my mom. But here's the thing: I'm 21. I graduate college in May. I pay my own bills. I buy my own groceries. I make decent grades (not to mention the fact that I'll be the FIRST person in my ENTIRE family to actually GRADUATE from COLLEGE!). I've been so afraid of losing a relationship with my mom that I'm scared to actually figure out who I am, which is what she has been pushing me to do.
Wait. I take that back. My dad has been encouraging me to figure out who I am before making any life decisions (like a career). My mom wants me to make a career out of what I've gone to school for, which is what she's paid money for. And they wonder why I'm depressed?!
I can't tell her that I plan to take at least a year off of doing theatre and just work. Because she says that she paid money for this education, so I need to make a career out of it. (Yes, she's said this.) I can't tell her about my relationship with my boyfriend (which will be for a year come Dec. 31) because she criticizes him and our relationship. Sorry mom, but I don't think Prince Charming exists in human form. And I'm pretty damn sure you and dad weren't the best of people when you started dating, nevertheless when you got married. Yeah, my boyfriend has some issues. So do I. Its not like we're getting hitched anytime super soon! Neither of us can exactly afford it.
And what do I do if I find something I believe that differs from my parents? Oh God forbid. That happened with my brother and they fought over it. Yeah, they still have a decent relationship. But I get the feeling that's because my brother's always been the "different independent one." I've always been the "never question anything" one.
I'm so beyond frustrated. What am I supposed to do?