I laughed so much at the end of the working day, just joking with the guys.

Ahh so maybe that's the cause of it then resentment of characteristics you share but don't like. Might be better to help someone out of their shell than to shake the shell.

There is a woman, a manager at my job who thought I was an easy target because I'm introverted. I reported her but apparently I wasn't the first person to complain so we had to talk with a witness present. Very awkward for both of us but I explained to her that I took it personally and that I don't want to have the atmosphere.

She seemed to be nice after that maybe she listened or maybe she's under investigation but who knows. Even a worm will turn.

It is good to be strong, competitive but attacking those who will not fight back is not strong.

Was it somebody who often catches hell about everything? He's probably not mad that you were poking fun at him because we all do that to our co-workers but maybe spiteful about the workplace itself. I know I feel that almost constantly but if somebody is joking around I can lighten up for that.