#3 Becky's ego costs them the titles
Even since adapting to the Man gimmick, WWE has been promoting Becky Lynch as a more cocky character on-screen. Her demeanour during her entrance and while cutting promos show that she has embraced a rebellious attitude to her character.
During the opening segment of the Raw after the Stomping Grounds PPV, Lacey Evans & Becky Lynch started to brawl in the ring. When Seth Rollins tried to pull his girlfriend apart from the fight, Lynch gave him a stiff shove giving him a stern warning that she fights her battles alone.
That wouldn't be the case at Extreme Rules as both Superstars needs to work together if they want to walk out with their titles. If Lynch brings this attitude to the match this Sunday, we could see her losing the match and cost Rollins the Universal Championship.