That, of course, is not what happened; what did happen is that Mira's suggestions were fought at every turn and she herself depicted as an ogre who wanted to boss Deanna and everyone else around because she didn't know to sit back, shut up and let Deanna have things her own way. That last bit explains why things reached the state they did; simply put, Deanna would not admit that a wedding is not primarily about the woman in the white dress. Most, if not all, cultures believe that a wedding is a celebration of the union of two families as well as a chance for the mother of the bride to take center stage and demonstrate how good a job she did raising the bride-to-be. Deanna's fragile ego couldn't handle not being at the center of everything so the same woman who wrote a nasty little missive exhorting us to hate Mira for not meekly surrendering to the authority of HER DADDY!!!!!!!!!! got a bunch of gullible saps who also hated taking a back seat to people to steamroll a sitting duck.
This was called a happy ending because the idiot writing it is also loaded with infantile power fantasies and the need to smack down anyone who might potentially stand in her way.