I think, in college, that a lot of people are with that Mr/Ms Right Now because they're just damned lonely, and it's convenient to have someone to talk to/eat lunch with/screw/watch movies with. The weird thing is, that most of these people are planning to break up after graduation. It's like, they were good enough to mess around with during college, but they don't want to be tied down to that person after college.
Maybe since I know Mr. Munchkin is Mr. Right, I am more critical.