Star Wars
Star Wars started to go "downhill" when the prequels started coming out in 1999. The movies lacked the same charm and simplicity that the original three had to offer, and the continuation of the series has combined both philosophies that went into the prequels and originals. This formula didn't hit. Critics bash the new Star Wars movies for the rampant fan service and lack of originality.
Batman v. Superman: Dawn of Justice
Here's a pro-tip if you haven't watched this movie, it takes two hours to get to the actual "Batman v. Superman" part. This movie is a cash grab, through and through. Filmmakers saw an opportunity to use two big names to make a ton of money, so they did. Can you really blame them for that though? Most critics hated this movie, but casual viewers overhyped it. Either way, this movie is overrated.