Citizen Kane
No single movie in human history is overpraised as much as Orsen Welles' 1941 classic. Yes, good movies deserve criticism too. It's important to note that the positive energy around Citizen Kane is large because people are told that they should like it by critics and cinephiles. Even Richard Elfman went out and stated that Citizen Kane is massively overrated.
Mean Girls
Mean girls received an entire generation's praise. But, when it comes down to it, it's just a movie about toxic people treating people poorly and then getting what's coming to them. Critics feel mixed about this one, but viewers tend to love it.