Hi Jesyka,
I know someone who has OCD and oh, when she gets onto something she does not let it go. I know you said the person can control her behavior--but I think it is much for difficult for people with OCD--they seem to have some sort of persistence mechanism in them that is set to overdrive. A person I knew told me the same story (about her being angry at someone else) for years. <--years. And the incident was even further back). When my last nerve snapped I finally said, "You've told me that before--several times before. Why Why do you keep bringing that up?" She said, "Because she made me mad." So after that she didn't tell me that story again. But assuming I ever see her after we are all let out of our homes -- I am guessing she will eventually cycle back around to that same story. <--that is what I mean by some sort of persistence mechanism.

I'm guessing because your reaction was different from the others--she is chewing away at it.