Lea Michele
Lea Michele had her time on Glee and that was basically it. Ever since her castmates outed her for her bratty behavior, fans haven't been interested in the has-been musical star.
Ms. Not-So-Nice
Michele even had a stint on Scream Queens, which was semi-popular. Yet, she was outshined by her castmates and most people don't even remember that she was on the show. When you have unremarkable performances and a bad attitude off-camera, people are going to stop giving you the time of day.