During a last theater or musical show there are always extra jokes and bloopers...why?

Well from being in theatre for 3 years, I can tell you it's usually because it's your last chance to do what you want, so you want to make it as memorable as possible. It's your last shot to have the best time ever. And recently I was in Hairspray, and the guy who played Edna popped his boobs (they were balloons) during the bows of the last show, and I, as Amber, did some riffs and went all out.