My ocd is worse in busy places too. I think it is because with more people around, who are doing more things, it gives me more things to have to rearrage in my head, or more things to be bothered by because of all the things that are going on. I'm not sure if that sentence actually makes any sense, but I tried. ;) This doesn't really answer your question, but I thought I would just let you know that I can relate..
-Kate