One example: Felicity on Arrow. She was the fun, comedic character that lightened up the show. That was necessary in the first two seasons, and we all loved her for it. Unfortunately, the writers made the mistake of listening to fans and decided to make her Oliver's love interest, and everything went straight to hell after that. That writing love stories is a major weakness for the Arrowverse writers didn't help matters. As a result, Felicity is now one of the shows biggest problems (or she was until last season, when the newbies took over that role and made her look good by comparison.)