I always say hello and may chit-chat a teeny bit, but rarely talk more than than. My life is just so busy, and I almost always have work to do while on the plane. I kind of treasure the quiet. So after lift-off, I typically slip on my Bose headphones and leave them on until landing. There have been a few cases where I had a great, long conversation with a seat mate, but that's a pretty rare event for me.

I have heard some cool stories about people talking to seatmates. I remember reading in an in-flight magazine about how some people completely lie their way through conversations with seat mates, claiming to work in a completely different profession, live in a completely different city, etc. Being in a situation where you'll likely never again see the person you are sitting beside, some people have a bit of fun with it. The article (or perhaps a letter to the editor the month after the article appeared) talked about a case where someone claimed they were the chef at a particular famous restaurant (in LA I think). In fact, the person they were talking to was the chef at that restaurant. They ended up getting married.