I find meat itself has no flavor - you can distinquish between chicken, turkey, beef and pork but without spices of some sort or other, they're all bland and tasteless. But in almost all cases, a bit of salt "wakes them up". That's the starting point. From that point on its rubs or sauces and toppings and the choices are endless as well as cooking methods.
Back to the question, when it comes to burgers I personally like them not too thick - a "quarter pouind" patty is almost too thick.
I like a medium ground beef. I like them fried - cooked right through but still juicy.
Buns get buttered on the OUTSIDE and fried in a seperate pan - don't understand why anyone would toast a bun on the inside !! I like the bun squashed down a bit while frying. Fried just enough to put a sear on it - not blackened!!
I like a cheesburger so the cheese goes on the burger when the A side is cooked and the burger flipped to cook the B side. A lid goes on to keep the heat in to melt the cheese.
Dressings are your option but I like:
mustard, relish, a thick slice of onion, a slice of tomato and a slab of banana pepper. Bacon is optional.
IMHO ketchup does not belong on a burger unless you're eating it plain.