I have so much bottled up how can i let it out without harming anyone?

most teens complain about there parents "i hate them, they don't let me do anything" and rebel with the parents but the parents aren't necessarily in the wrong. In this case i just believe my parents are terrible parents neglectful, ignorant the works, i won't continue to complain i will get to the point. I try my hardest to not be affected by my parents and go on. In this way though i have always been "too nice" i guess. I am nice to everyone almost all the time to my friends and even my family i bottle up everything else because i just don't want to be negative, mean, bad or whatever. After 19 years i don't think i can take it anymore though but i don't want to just let out bottled emotions on people i care about and not even my parents what can i do?