If DnD is embarrassing to do as an adult, then I don’t want to be not embarrassing. What’s wrong with playing pretend? We do it all the time in socially sanctioned ways. We pretend that we want to be doing our jobs, we pretend to not care that we just paid $7 for an iced coffee, and we pretend we want to «get lunch» with that friend we have no intention of «getting lunch» with. 

DnD is a healthy way to channel our two-faced energies. If we’re going to lie anyway, might as well lie about fun stuff like being a dwarf with a dark past and a desperate need to prove himself to his estranged dwarf father. Now that’s a good lie to tell. Luckily there are plenty of people out there who also feel that way, and are thus willing to lie to one another, and with one another. And that we have memes that celebrate those lies.