What is D&D?
Impossible kingdoms, improbable dungeons, silly monsters, a superabundance of magic and magical items that somehow do not affect society at large, convenient currency accepted everywhere (and an all-cash economy based on extensive gold coinage), language same, whittling combat, character classes, levels, spell levels (that specifically do not correspond to character levels), "fire-n-forget" magic, several hundred planes of existence, adventuring accepted as an occupation, High Middle Ages society meets upward mobility and meritocracy, magic that is great at maiming and destroying yet cannot ease birth pangs or truly aid crops, high level characters running around with abandon while kingdoms remain stable and have precise histories often going back 1000+ years, elves at 100 not knowing as much as a human at 18, monster overpopulation, many core races living together in peace and harmony, a "mirror world" underground that has neither peace nor harmony and is much tougher than the world above...
I think this is why I play rpgs and D20, rather than D&D...