What's your favorite fast food burger?

The other day I drove by a Five Guys burger joint.  It was 10:37 in the morning.  I had been wanting to try this place for a long time, so the fact that most people were still waking up and heading to Starbuck's  at that hour was only a slight problem for me.  Slowly, I drove by and read the door.  It opened at 11am!  That's still pretty early to eat a burger : (

But you're only 38 weeks pregnant a few times in your life, unless you're a Duggar, so I decided to go for it.  I walked in by my lonesome.  This girl below came running towards me, and very joyfully asked me if it was my first time.  "Why yes!" I said, also very joyfully.  Gosh it was a joyful experience.  She helped me order a Little Cheeseburger (one patty) with Grilled Onions, Pickles, Ketchup and Mayo.  Simple.  Oh and a bucket of fries.  And a diet coke, sorry baby.    

By the way, not okay with listing calories on menus.  I mean why, why why why.

Anyway, 560 calories (oh plus the buckets of fries) later, I had ZERO REGRETS.  It was so damn delicious.  Tasted like it was fresh out of a local 1950's diner.  I think my favorite fast food burger yet.  Better than In and Out, better than Fat Burger (Carson said, I've never had).  So I want to know - have you had Five Guys?  What's your favorite fast food burger?  Let's discuss.