I would have to say jumping off the cliff without Jacob, 1. if she would have waited Alice wouldnt have seen and thought she was dead and wouldnt have shown up, Rosalie wouldnt have told Edward, he wouldnt have gone to italy, there could have been a real chance between Bella and Jacob. 2. if she would have waited she wouldnt have almost died.
the most dangerous idea bella had waz jumping off the cliff. she should have told jacob that she wanted to go cliff diving, she just caused more problems, edward thought she waz dead so he went to the volturri to die himself. she's Sooo stupid sometimes!