Also, I'm not sure I'd call it "happy." I'm much more likely to cry when something Xtremely ... nice(?) has happened. I have no idea what to call it, but I'll tear up briefly if I've just helped an old lady carry her bags to her car. Or see someone else do it. What's that called?
Some ridiculously cute things will make me cry. I got air time on some tears while watching the Budweiser horses/puppy ad. It was like when cartoons cry and the tears shoot out to the sides.