I once met a guy on a train, who turned out to be a multi-millionaire, who told me his investment strategy was based entirely around this very phenomenon. I still keep in touch with him from time to time. Fascinating guy.

More personally it annoys the hell out of me and I avoid doing it. It's the same of the train. I had a woman get very ratty with me the other day because I didn't stand up just because everyone else did (she was window and I was aisle). I wouldn't have minded but we were at least five minutes from arriving in the station!

There are probably all sorts of studies on this but I suspect the main reasons are 1) herd mentality 2) impatience. The levels of impatience I see on a daily basis are truly scary.