I don't know if it's because the holidays are coming up, and you see red, green, fake snow and lights everywhere, but something in the air is making BART passengers very social and friendly to each other. I've been seeing strangers striking up conversations randomly and talk the entire way through the ride...some even go as far as exchanging business cards!!
BART passengers generally try to avoid talking to each other. We usually bury our faces in reading material, sleep, or completely tune out to surrounding noises with music. It is quite rare to see someone say, "Oh! I like your phone! Where did you get it?" and start blabbering away from there on.
I have not yet sat next to someone who wanted to chat...I don't know if I want to. I love the holidays but when it comes to socializing early in the morning when I'm still sleepy, or socializing in the evening when I'm completely drained by work, I remain a Scrooge! However, in my defense, I will always be polite should someone talk to me!