IMDB should list your age when you review a film
Twain said something like, "of all the arts, humor ages the worst across generations". That isn't the quote, but I couldn't find the real one.
What's funny to you depends largely on where and when you grew up. IMDB gives us the where (on reviews though not on forum posts), but with classic comedies, the reviewer's age can be the most important factor.
Reading the comments and reviews for The Gods Must Be Crazy, I was wishing over and over I knew people's approximate ages. I'm not claiming that "kids today don't appreciate good humor" or anything like that. Simply that taste in humor, in general, changes over the years. There will always be young people who appreciate classic movies, but I imagine they'll always be a minority.
I have the same problem appreciating most of the "screwball comedies" from the 30's and 40's, though I'll always give Cary Grant films a shot after learning how much I liked his late works.