I feel like Supergirl used to be good. Or at least by my standards at the time until I watched Young Justice, Doom Patrol, and Constantine which alongside Human Target are some of the best superhero shows I've ever watched. After season 2, I feel like the show went on a really fast downward spiral until it felt really bad. That combined with the fact that once season 4 started, the CW decided that since Superman and Supergirl were basically like the personification of the American way, every single episode had to have a political message behind it made it pretty much unwatchable after a while. Also, the writing is some of the worst out of the three CW shows I've watched, The Flash, Legends of Tomorrow, and Supergirl.