Is it normal to purge thoughts from your mind

Sometimes when I think things that I'm not supposed to think because they are rude or embarrassing and, I'm a slightly a lot more than a little bit paranoid that people can hear what I am thinking. I will count as high as I can until I don't remember why I'm counting. For example: If I am at the gym and I see a hot guy with his shirt off and in my head I'm like "Damn!" and I'm relatively certain that he somehow heard (which would be incredibly embarrassing for me) I will force myself to think "1,2,3,4,5..."