What is the common ground? Sports. Quibble pants has a girlfriend, and his girlfriend has a daughter. The daughter is really into sports, Quibble pants isn't, so he asks Rainbow Dash all about it.
So, the episode wasn't bad per se, it's just that Wind Sprints comes across as too unlikable, since she's constantly pressuring Quibble pants to like sports. They only "find common ground" because Quibble eventually caves in to that pressure and asks her to make him a fan. This episode needed a rewrite. Have Wind Sprints not really mind that Quibble doesn't like sports, and have the both of them find something that they do genuinely enjoy, some actual common ground.
