My 1st grader also did this sort of thing in pre-school. He'd "confess" every day when I picked him up all the things he had done. Now mind you, he virtually never got in trouble and the things weren't bad at all but it scared me pretty bad when he would do this. I basically would start talking first and get his mind off of it and eventually he did stop. He doesn't have any of this type of behavior now so I don't know if he just out grew it or what.
I have a relative that is OCD and it is something that has only gotten worse with time, not better. And it affects most aspects of life, not just something here or there like good-byes or going to bed. I don't know how you know it is OCD until it has continued on for a long time and does interfere with regular functioning in most aspects of life.
It sounds like many kids do exhibit this type of behavior at a young age, so yours will most likely out grow it as well. Or if it is in only 1 or 2 areas at an older age I wouldn't think it would be anything to worry about either.
(but I am definitely no expert on the subject)
