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.
I'm cheating a bit with a 1994 movie, but I genuinely enjoy watching Wagons East! It has 0% on Rotten Tomatoes, but I like it. I'm probably the exact target audience: I like westerns, and I like movies that make fun of them.
If the 90s is cheating how about a 1980 film? With the caveat that I haven't watched it since the 90s/00s and my opinion may change if I watched it again. But I really enjoyed Robert Altman's Popeye film, and was quite disappointed to find out it was an unloved flop. 58% critic score, 39% audience score.