There's a huge difference between a little teasing between friends who know you are just messing around and constant, hurtful jokes where a person doesn't know when to stop. The main difference being that with the former, the other person/people laugh with you, with the latter, it's just someone laughing at you. I can honestly say I don't tease people that way. I try very hard to be careful about what I say. (Not saying I'm perfect, there may have been a time or two when I didn't think about it, but at least 98% of the time, I don't poke fun at people.)