I think the biggest problem with "hooking up" is that it's done mostly for selfish reasons - that you want to have sex. The other person isn't really taken into account, and I think that's the key here.

I'm not a very old person by any means, but I've found that good sex is a result of two people truly caring about the other and hoping that they're enjoying it at a high level, and doing what it takes to make that happen.