Are you a dysfunctional veteran? I know I am

Tone is everything.

I'm told I'm mean a lot too. But I think it's just because I say what I think no matter if it's a good thing or bad thing. Don't feel the need to change for others.

There's a girl at my job who's the same way. She comes across as mean and/or snooty. I've actually had customer complaints about her. I think that she's actually just legitimately mean and snooty though she tries to say she's a nice and good person. Actions speak louder than words, OP. Your tone of voice and facial expressions convey more meaning than just your words.

I'm the same way and you could never please all of them. They're all just gonna be a bunch of assholes.

This happens to me all the time. If you figure out the key, let me know.

Don't worry OP, I face a similar battle every night at work. Just be yourself, the right people will like you for who you are.

I can relate. Seriously. You do you, as long as you like who you are.

My classmates say the same thing to me

Your "niceness" was obviously forced, which comes across as condescending. If you can't be genuine with your attitude, people will notice, and fake kindness often comes across worse than unthinking cruelty.