The dancing was too goofy. I could see if he danced with Gwen Stacey provokingly from the beginning, that would have worked. But the whole jumping and jacket wind in Gwen's hair just made it goofy. I understand this is Spider-Man but come on, its suposed to be a serious movie with funny moments here and there, if you want funny, make Spidey wise crack. (which the movies needed more of).
The crying was too much also, Peter should have just got pissed when MJ broke up with him, not cry like a little *****.
The emo-parker was also not needed. A black coat would have suited well. Make his ACTIONS and ACTING make him seem darker.
MORE black suit Spidey in action also. Show him beating common street thugs almost to death, THAT would have shown his dark side.
Honestly, it could have still been funny with wise cracks, didn't need a goofy dance number. I'm all for comedy in this movie, not goofy stuff though.