Why Can't This Be Love?

I really, really like Dungeons & Dragons (5th Edition). Like a lot. It's a rock solid game that strikes a great balance between crunch, approachability (is that a word?), and ease of play. I've played several characters in 5e games and enjoyed all of them. I own a slew of books in the game line. My group is composed (except for myself) with players who all got exposed to the hobby after 3rd edition, though none of them played 4th. They're all glad to play 5e. Seems like the perfect fit, right?

Then why can't I run it?

I don't mean physically. I mean psychologically. I sit down with the 5e books, pour through these beautiful pages, think up all kinds of ideas, start letting ideas spin for an amazing epic fantasy campaign worthy of song and legend (or so my ego tells me). But when the time comes to actually do the work and put pen to paper, my resolve fades. I think, "Nah, I'd rather run White Box (or Basic Fantasy, or Dungeon Crawl Classics, or Castles & Crusades, or Swords & Wizardry Complete, or Labyrinth Lord, or The Hero's Journey, etc).

Why is that? What gives? I want to run 5e. Or at least I think I do. So, what gives? I know my players will enjoy themselves. I know I'll enjoy myself. I've got a plethora of material so a ton of prep isn't necessary. This has been nagging in the back of my mind for the past year, but in the past few weeks it' genuinely bothering me. So, what gives?

I wish I had an answer.