The top reason why Supernatural became worse after season 5 in particular is because of certain staff changes that occurred at this point. From the start, Eric Kripke was the creator and main showrunner of Supernatural. He gave the show its dark, grungy ambiance and horror-centric themes.

Metatron. Metatron is an antagonist on Supernatural and fans despise him a lot for the way he uses others to achieve his goals. One of Metatron's detractors is carryonmywaywardson, who points out, "Metatron really is the worst among all, he's a coward, hiding and using good people."