Melissa McCarthy skipped cousin Jenny's wedding to Donnie Wahlberg because they are fighting. According to the National Enquirer:
"Jenny feel she helped Melissa get a leg up in the business. But now that Melissa's career is skyrocketing, Jenny feels she doesn't have time for her."

Melissa worked as a production assistant on her cousin's short-lived variety show in 1997 and made an appearance on the show. But Jenny also reportedly told her that she'd need to lose weight is she wanted to advance in Hollywood. "That really hurt Melissa, and now she's having the last laugh," said the source. "She's proving you don't need to be a size 2 with fake boobs to make it!"
Melissa is an outlier of course. It is definitely easier if you had boobs like Jenny.