The fact that World of Warcraft, a mmo that came out in 2004, is still the best subscription MMO. My wife and I were playing it together 5 years before we had our fist kid in 2009. Now we have two children and both of us wish we had time to play it. THAT makes us feel old.
The funny part? we both thought a mmorpg was a dumb idea back then since we were obsessed with Warcraft III...