It could be a bad movie, a TV show, 7 Layer Crunch Wrap, the smell of a good fart, whatever. Just something that you damn well know sucks total ass, but that you enjoy openly and without the hint of regret.
For me it's
These things are foul, they're bad for you, you can almost never find them, but lord, they make me so happy.
(a close second is the TV show "One Tree Hill").