A bad guy who really can't get over people not liking him back. Meanwhile, there's clearly one person that (at least at the time) actually did, as he has a son. However, nobody really knows who the mother is, except maybe Bowser Jr. himself.
A guy who accidentally travelled 1,000 years into the future, and thus is not (at least originally) current with the times. Has an alcoholic robot as a best friend and a tough one-eyed lady as his love interest. Adopted to the futuristic changes quite well over time.