If it’s true that the boss treats you differently than the rest of the employees it could be for several reasons.
1. It is possible that the boss does not like you for some reason. Maybe you inadvertently did something that he didn’t like. Maybe you are making him look bad without realizing it (like if you are doing more or better work, or work that was previously done by him) or he’s jealous of you for some other reason.
2. He could have some sort of secret crush on you, that he knows is inappropriate, so by treating you poorly, it makes him feel like he is avoiding the situation of having to deal with you without having sexual feelings (and/or possibly he’s blaming you for having sexual feelings towards you) or he’s pretending to be upset with you, so no one knows that he has sexual feelings towards you.
3. He may have heard some negative gossip about you which might be true, or might be untrue.
4. He may not like you because you’ve done something that you are not admitting to us, something that makes him look or feel stupid or angry, but it’s possible that whatever you did was not criminal or even an actual fire-able work offense. Here’s an example that I’ll share with you from my own experience. There was a woman at work who would always let the door slam in other people’s faces. She would never hold the door open for anyone, even if they were carrying a load of boxes, not even if they were mere steps behind her. She would ignore any co-workers who were “below” her on the social step ladder. She was rude, but not in a way that could get her fired. She was also a very poor communicator which rubbed almost everybody the wrong way. Most of what she said came across as rude and opinionated and pretentious. No one liked being around her. She also always had a sour look on her face, except when anyone “above” her social station in the company was around, then she managed to pull it together.
I’m guessing that you know more about why your boss is acting like this than you are letting on. Unless you are extremely naive, I think you probably know, or have a pretty good idea about what’s really going on here. People gossip, so someone else has probably given you or one of your other co-workers a pretty good idea of why the boss is acting like he is. Find one of those people and ask them.
Don’t just ask them if you’ve done anything wrong. Most polite people will say no. Ask something like this, “Hey Barb, over the last few months I’ve noticed that Mr. Boss has been doing X,Y and Z (give specific examples). I was wondering if I’ve done something that has rubbed him the wrong way. It seems like I’m the only one he acts like this around. Does it seem like that to you? Is it possible that I’m doing something inadvertent to upset him?”