WTF girls?

y do girls always seem to go for the pot-smokin guys,but never the nice guy who's always there for them? y dont girls ever go for the guy thats always there for them when there boyfriends not and things like that. they always seem to go for the douchbag dudes and never the ones that are always there for them. Do they honestly not see whats right infront of them? (and yes this is pretty much from personal experiance)