The saw movies. The first few made sense somewhat in how they were connected but then it went from hard to believe to no sense at all. Like this guy learned how to be a killer from the master and then by the 6th movie its the guy who learned from the gardener or the taxi driver of the assistant of the disciple of the master. Also the movies are characterized by having a big twist which after the 5th or so movie having the big reveal/twist it just gets corny.