Well I would assume Sakura gave up that one when Sasuke "King of Hax" Uchiha decided to try and use her as a sharpening tool for his Chidori.
As for Naruto, he maybe a bit on the...low end of the intelligence spectrum, but you can't say he doesn't know what needs to be done at the right time. His instinct and battle tactics almost rival Shikamaru in sheer brilliance and effectiveness. And unlike Sasuke, when Naruto gets his hax, it usually STILL isn't close to a free win and he has to work for it. So any stupidity he makes up for in daily life by way of ignorance he makes up for elsewhere where he has great moments of clarity.
Plus you know...Friendship no Jutsu and the fact that if girls can't fall for dumb guys the world's population would probably be cut in half (...possibly for the better but still).
Plus it never seemed that Sakura never really got past the whole schoolgirl crush phase of her love of the douche, not that she ever really had time to. Now any love she has for Sasuke immediately turns into guilt for putting Naruto through LITERAL hell in trying to get his ass back. Plus like I said...think that whole thing ended with the whole murder attempt. Hinata...yeah, she decided to go face to face against (at the time) the biggest badass the shinobi world had ever seen just to save Naruto, and decided then to confess.
Tenten...crush on Lee...yeah I'm sure Neji will just pull a robbery on that one. Not that it matters, it seems like more of a loss than anything to have Tenten go after you. Imagine the misfortune in your life...think of the children...