As a child a burger was just meat, bun & ketchup. Didn’t have a cheese burger til I was oh 14 I guess…thought I was being very daring. 
Liked it! As an adult I like sauteed onions…properly if you please! i.e. browned not just shown to the griddle & tossed on it…like the steak & cheese subs we had last night.
and yet another example of “appetite makes the best sauce”… coleslaw. never ever would have done that on my own but after a 12 hour bus ride going to work for the summer at Dad’s restaurant & getting there about 8pm I was STARVING & was given what was then called a “California Burger” on the menu-- meat, cheese, BLT & slaw & I think ketchup too but it was wonderful! I’d still only order my default basic ketchup & burger or cheese burger but won’t turn up my nose at a slaw burger.
