Case in point, I saw a 7 month pregnant woman on the subway and no one would give up their seat. One guy was actually reading a book about money, just to drive home the fact that he was an asshole. The woman told us that 80% of the time no one will give her their seat and when they do she is so overwhelmed that she wants to send them flowers.
So why not do something kind? Wouldn't it be nice to make someone happy enough that they'd like to send you flowers?