Jo had rivalry with Heather, Cameron, Anne Maria, Lightning, and Brick: which all ranged from fierce competitiveness to friendly competition. (Excluding the little cuts of beef she had with, well, everyone <3)
Jo also proven she could be a friendly face with Duncan.
Also the competitiveness with Heather shown that she could at least hold a penny to one of the best antagonists and competitors of Total Drama, which isn't really hard to believe when you consider Jo's alliances and strength
IDK there's just something great about Jo