A boss that gets up and follows you into the bathroom to make sure you are "doing your job" or makes passive aggressive comments to you during your lunch about how he didn't think you were in that day.... or what about a boss who works 9 hours straight (no lunch, no breaks) at his desk and anticipates you do the same without question, while the rest of the company does 8 with breaks and lunch... and micro manages 1 person in the company, which is you.
Because he doesn't trust you. I'm not saying he's right to act that way, he's wrong, but that's the way some people are. It might get better if you stand up to him. Or you might get fired or hit in the face, YMMV. Ask your colleagues if he was like that in the beginning with them and then eased off.