Could you perhaps explain that to my wife?
I’ve learned all manner of things from roleplaying that I probably wouldn’t have otherwise. I’ve researched medieval sailing and navel warfare. I learned how to shoot a longbow and swing a sword to bring more flavor to the game. Researched heraldry and historic fashions.
Of course all this medieval research came in handy when I temporarily lost my mind and joined the SCA and when civilization falls, I can be completely self sufficant.
I’ve met great people through roleplaying gameing groups from all walks of life. Lawyers, Accountants, Web Designers, Scientists, history buffs, Engineers, computer programmers, photographers, writers, Customer Service, Tech Support, Psycologists, Artists, students and domestic engineers.
I joke about my bum gamer friends, but when the shit hits the fan, I couldn’t ask for better, truer friends than the ones I’ve made from either my ftf games or my online games.
I am more than a little intrigued.
Your wife didn’t write this, did she? 
My husband is a Dungeon Master, and he considers D&D to be his necessary creative outlet. It is also a social activity, and he thinks it’s fun. If you’ve ever played the computer game “The Sims”, you’ll recognize that an activity that fulfills three “needs” at once is pretty valuable. Of course, if you don’t like it, then it’s a “waste of time”.
I’d be happy to, but I’m not sure that it’d do much good. I’m lucky enough to be with another gamer, so I’ve never had to explain myself. Heck, I’m the one that got her into gaming, back in highschool.
“I didn’t spend all that time playing D&D without learning a little something about courage.”
Gaming is just gaming. It’s neither a waste of time, nor an indicator of anyone being smarter, more creative, better, etc., than non-gamer types. Now, personally I’ve enjoyed it for years and years, but I really don’t think it gave me any kind of superior mental powers.
Lord, how I love roleplaying. I’m not especially devoid of creative outlets outside of it, to be sure. But there’s nothing like bellying up to the table, “cradling a pair of 20-siders and feeling the ol’ dice fever” (As the Knights of the Dinner Table put it).
All week at school my thoughts drift to the modules I’ll run that weekend. I typically GM, perhaps 3/4 of the time. I play D&D, Deadlands, Call of Cthulhu, and Champions: New Millenium.
My friends in my gaming group are about as far from the stereotypical gamer as you can get, as well. As am I, for the most part (I am pretty heavy, though). We’re all motivated, creative people who enjoy living through someone else’s life for 8 hours a week (the players), or love the creative challenges involved in Gamemastering.
In short, it is certainly not a waste of time.
Studied bumping bellies? Now where was THAT when I was in school? :)