I do train my dogs, I'm always teaching them something new. Don't judge too much with the owners who have unruly dogs, though . I have a big dog, and sometimes he gets excited, and he wont listen for anything. Once he calms down a bit, he listens wonderfully, but if anything gets him excited, it's time to play.
As for training, one thing I like to do, is to teach them vocal and visual cues. So, my dogs know what sit means, but they also know when I make a quick pointing motion at the ground, that also means sit. I try t teach them silent commands for most of the tricks they know, but some don't work. I can't get them to speak from a visual cue, but I'm working on it, haha!