"Hey There Delilah" isn't a bad song at all in and of itself. Intrinsically, it's just a catchy acoustic ballad about a guy who misses a girl. There's a nice little McCartney-esque string quartet backing it up, it's catchy, and the whoa-ohs at the end are fun. Where we get into treacherous footing is when douchebags try to play it at parties, and to what extent you can let that ruin music for you, I'm not really sure. Dave Matthews was shitty before broterpretation, so no loss.
I won't defend Soulja Boy, though. It does suck, of course, but it sucks in an easily endurable way. Some awful songs make people grab rifles and ascend belltowers for very good reason. This isn't like that, though! It's just bad in this sort of phlegmatic grinding way where all you can do when you start hearing steel drums and YOOOOOOOOOOOOOUUUUUUUUU is go "oh, hrmph, it's that stupid fucking Soulja Boy song again," sigh semi-dramatically, and quietly wait out the storm. No, you know what it is? It's similar to that stratum of local commercials that are sort of endearingly annoying but not fun-bad enough to wholly embrace as being Fun-Bad. Soulja Boy is Peter Francis Geraci.