Believe everything you hear. Just don't act on it without good reason.
I used to have a temper and would pick fights with people I thought were assholes/douchebags/worse people than me.
To be fair, I grew up around criminals and am pretty ethically flexible myself.
A lot of people might say "but criticism is good!" "that's BS advice!" "fuck off, I'll challenge whatever I want if I don't agree", but if you heard that some guy cut the ligaments out of someone's neck, stir fried and fed it to him - are you reeeaally going to argue with this guy anyway?
Plus, it's helped with a lot of things. Got my through high school. Formed my opinions outside high school through my own research, and didn't question shit all during school. Just took the notes, parroted it back to them, and left.
Basically: Your opinion is worthless, thereby irrelevant. Just get your work done and fuck off.
...There's a few other stellar pieces of advice I can think of...but I smell of cut grass, fig trees and dog shit. So I'm going to shower.