My post from Dragonsfoot:
I met my wife and the best man at my wedding through a gaming group.
I learned to quickly and intuitively apply statistics. Most people cannot figure the results of this type of problem: "Ok, I have a 4/6 chance of opening the door first try... Then a 2/6 chance of getting a surprise round... Then a 45% of landing a hit... And an 80% of it being a one-hit-stop before the goblin takes otu the hostage. So what are the chances of getting this done in one or two rounds?" Obviously that exact problem does not come up too often in life except for those on the SWAT team, but there are many events involving probabilities in life and most people suck at the math.
I learned to turn verbal descriptions into graphical maps/diagrams, and back again (mapping 101 and room description 101!).
I learned to put myself in the mind of another type of character -- or even a hideous cunning monster. I now do threat analysis professionally as a living. Most people are unable to even imagine how a suicide bomber or assassin or even common criminal thinks. Being able to break out of your own frame of reference is very helpful.
I learned how to game out multiple courses of action, including detailed tracking of costs/consumables/durations (name level magic user spell planning! AAAGH!) and determine which is best. THis is helpful for many things, whether it be figuring out how to plan a family vacation or a major business move.
I have been able to slip "antithesis of weal" into conversation a few times. I get to smile every time. That phrase is like a secret uber geek handshake, by the way.
I learned that knowing when to commit your last reserves, and knowing when to cut your losses and NOT open that "one last door" are keys to success. Not just in games, either. The key skill in D&D, I think, is having the judgement to balance risk and reward in both the short and long term. That is what "one more door" is all about. Evaluating risks and rewards in a rational, cool headed manner is an important life skill, but so is knowing when to gamble and hope for a natural 20.
Finally, I learned how 1E initiative works. It took four years and enough time to have earned another minor in my undergrad but I think I finally have it licked.