Children have the capability of making you feel very, very old.
I dropped my son off at a community event tonight where, among other things, they watched cartoons. He had never seen The Flintstones before and announced to me excitedly, "Daddy, look, cartoons with those guys who have the cereal!"
This is almost as bad as the time at work when, a few years ago, I made a reference to the "Sweathogs" to my recent college-grad assistant and my college age intern and was answered with blank stares. ("Sweathogs" - they were on "Welcome Back Kotter," a sitcom starring Gabe Kaplan - just Google it.)
Now I check on this when I interview possible job candidates. It isn't a job requirement - but I'd like to know so I can avoid the blank stares.