Ariana Grande
This Nickelodeon star-turned-pop sensation has had her fair share of issues in the limelight. Remember when she licked a donut then put it back? Yeah, not the best impression. Many fans might recall Grande's disastrous contest-winning meet and greet session in 2013. The singer only spent around 20 seconds with the contest winners before going back into her dressing room. Her team cited it as a "safety hazard" but the fans involved said that she just didn't want to speak to her followers.