The "Mission: Impossible" series is another example. For many people, the second movie is considered to be the worst in the series. However, for me, it is --by far--my favorite of the films. It is, in my mind, a John Woo masterpiece with several of my all-time favorite movie moments (the heroine injecting herself with the virus and the twist with the masks). In comparison, the other films are largely indistinguishable from Bond or Bourne films.
Other examples of this include "Red," "Red 2," "Mr. & Mrs. Smith," "Ballistic: Ecks vs. Sever," and "Freejack." Each of these underrated movies had entertaining action pieces with goofy moments and some aspect of lighthearted romance. I'm certain that there are others, but these were the ones that came to mind. I can watch them over and over again even while knowing that most people don't think they are that good (although "Red" is usually pretty well liked).
I think this might be why the current Marvel movies have been so entertaining for me. While I also enjoy deeper movie experiences, there is something about a popcorn flick that just makes me happy.