So I went to DQ and got a double cheez burg, took it home, took one bite, and immediately threw it away because it had mayo on it. And ketchup too. When those mix, the result isn't the least bit pleasant. I don't always remember to ask for no mayo because it doesn't always occur to me that I should have to because mayo as a standard condiment on a burger is un-American. It's the sort of thing the customer should ask for if desired, not something the customer should have to ask to be left off. Mayo goes on white meat, not red. Its flavortaste doesn't naturally mesh with burg. In the same sense, if you want ketchup on a steak, that's your prerogative, but you have to ask for it. It doesn't come that way by default because it's an abomination.