Is it normal that my boss keeps apologizing to me?

I had been working for my boss for about two months. He is a really nice person. There are about three managers who work for him. He is the General Manager. Since I have been there, he seems nervous around me. He stumbles over his words, and talks a lot. The one thing he does constantly is apologize to me for very insignificant things. These are things like bumping into me by accident at work, and not saying hello. Recently, he apologized for stepping on my toe. He said it was not his intention to do so. In reality, he did not step on my toe. He tried to apologize to me for seeing him cleaning the floors at work. I did not reply. A few seconds later, I hear him screaming at the other workers to stop talking and get to work. This is becoming common. I only see him a couple times a week. I barely speak to him. He usually tries to say something to me. One day when I was late for work, he called my cell and left a message about making sure I was ok. I had called a couple hours before that and left a message that I was going to be late. But his message said he got the message and that he wasn’t sure.