My colleague comes to my desk often and chats. He sits on the other side of the office. Some things he wants to discuss can be quickly done over email. Sometimes he can be very over-sharing and wants to work with me on projects (that he could easily work with others) but sometimes he won’t say hi. Is he just friendly and a bit odd? This has been happening for several years, but now that we are in the office, it’s more noticeable.