In most cases it's usually the guy who's all over the girl simpin, being needy, too available, thirsty, and putting them on the pedestal. Since they're given so much attention they don't even have a chance to show interest because the dick is already being shoved in their face. If just for once a girl had to actually work for a guy's approval I'm sure her level of interest would sky rocket but I don't think most guys understand this.