Inspired by the linked XKCD. Using 60% instead of 50% because that's an easy filter to apply on rottentomatoes.
I'll go first: I think "Sherlock Holmes: A game of Shadows" was awesome, from the plot to the characters ,and especially how they used screen-play to highlight how Sherlocks head works in these absurd ways.
The Super Mario Bros movie. It was really good but for some reason has a 59% rating on the tomato-meter, despite a 95% audience score. Very strange and it's why I just don't trust Rotten Tomatoes.
Rotten Tomatoes reviews always remind me of that South Park episode where Randy is a Yelp reviewer. It feels like they take themselves way to serious and forget to just enjoy the movie they are watching.
The plot was pretty straightforward (though often rushed). I see why critics would roll their eyes at another kids movie that plays it safe like that. It's not anywhere near the level of a Paddington or Fantastic Mr. Fox.
That said, it wasn't really trying to be that, and was all I wanted in a Mario movie: show me you respect the franchise, add in a bunch of easter eggs and references, and be at least moderately entertaining. I just hope the eventual sequels and spinoffs aim a tad bit higher.