Only read about half the thread so far, but I think this is a pretty good topic.
Personally, I love D&D, but I never ever talk about it to anybody whose interest I haven't already gauged positively. It's partly the leftover mental scars from having been a teenage geek, but also because I've discovered that most people who aren't already curious about D&D aren't really interested in learning anything about it. On the plus side, fantasy movies and video gaming have made it a lot easier to discover potential "new converts" to tabletop gaming.
One of my buddies is an IT guy for a public school board. At the same time our group (including him) was playing through Lost Mine of Phandelver last fall, he'd be relating stories about a fairly large group of kids he'd frequently overhear playing the same adventure in the library of the school he works at. We'd laugh about it because of some of the weird/ridiculous n00b-ness of the kids in these stories (lol Venomfang rekt them), but overall it was pretty impressive: he said that over the course of a couple months, the group seemed to swell to almost a dozen players, then split into two separate groups over some absurb preteen drama. If young kids are picking up this game by the dozen, the next generation of gamers will grow up without the same garbage stigmas that are apparently still kicking around.