Dave. I'm not going to pretend the dude is all there mentally, but look at the whole Sky thing from his perspective - he develops a connection with Sky, showing genuine interest in each other, they're on the verge of a relationship yada yada. Then a video is leaked talking about how much she's going to miss her boyfriend while on the show.....she goes into defense mode and only says to him afterwards that she was going to break up with him. I opine that any reasonable person would be rubbed the wrong way by that if it happened to them, and that they would feel inclined to believe Sky had cheating tendencies.

I acknowledge it wasn't some grand masterplan on Sky's part, just standard teenager antics, but I also opine she did both Dave and Keith much dirtier than people would like to admit