Is it normal to have ruminating thoughts of disliking your boss?

I am a part time sales associate and I have these ruminating thoughts about how I hate my boss every time she's there when I work and it causes me to have a disgusted look on my face sometimes or a mean face. I sometimes frown when I think about how much I dislike her but when she comes in my section I put on the fake smile and am polite to her when really I am waiting for her to trip and fall. She's such a distasteful manager. She plays favorites and talks to certain people more than others which underscores the fact that she doesn't treat everyone the same contrary to her stating that she does when I first started this job. She made a joke about treating everyone like shit when I first started out and I didn't like it. However, I kept it to myself. After this comment I knew she was going to come off as a bitch in the days ahead.

I work in the back of the store in the clearance section and am separated from the other workers so I find myself feeling a little lonely at times when there is no one working with me. However, I do not mind working in that section because there is not much to do there. I do mind rude managers and sometimes when I am talking to her she'll look off to the side. Completely disrespectful. She can be rude and downright moody. I have very ill feelings that are buried in my subconscious. I wish I could tell her how I feel but I want to keep my job lol. These thoughts are ruminations and I want them to go away.

I think that the root of these ill feelings towards my manager stems from disappointment with the fact that she wasn't that friendly manager she made herself out to be during my interview but ultimately turned out to be a bitch. I've also heard she's two-faced and talks about people behind their back and I have no respect for people who do this. Since she is my manager I have to respect her but deep down I wish I could call her out on her BS.

My friend also told me some crazy stuff about her. He told me that she told him about her sexual encounter with her boyfriend after not seeing each other for awhile. What manager tells an associate this?? It's clear she's not dealing with a full deck of cards.

Is it normal to have ruminating thoughts about hating your boss??