If you search for the "Maddie's First Kiss" clip on Lifetime's channel, you'll see a thumbnail of Abby grabbing and kissing Maddie. This seems sort of misleading, but since this took place before her kiss with Gino, that really was Maddie's first kiss.
According to Christi, Abby is way worse in real life than on TV, and if they showed us the real Abby, people wouldn't watch the show. We've seen Abby snap a few times, but has it ever escalated further when the cameras weren't filming (or they were, but it was edited out)?
In Paige's lawsuit against Abby, Paige says that Abby once pinched another girl on the team (not named, but not Paige) hard enough that she started bleeding.
By season 3, most of the girls had become more withdrawn compared to how they were in the first two seasons, and both Paige and Kendall had signs of burgeoning anxiety disorders. It was later revealed that Paige actually does have a pretty severe anxiety disorder, but Kendall doesn't appear to have a full-on one. Yet.
In season 2, Melissa originally chose Nia to perform "Silence" at Nationals. However, she originally stated that it was because she thought that Nia could do different. Though, when Abby asked who Melissa thought would win the most points, she said Chloe without hesitation. Meaning, Melissa only picked Nia because she didn't think she would be a threat to Maddie.
