The "Seattle Dog" includes cream cheese and sauteed onions and is pretty good. Normally I just do Heinz Ketchup - no othr ketchup is allowed in our house. I do like adding onions and 'kraut to a brat though, and prefer some fancy-schmancy mustard (brown, stone-ground, horseradish, etc) to French's yellow.
My wife and daughter put ketchup on everything, including steak. They also insist it be cook WELL. Last time I made steak (sirloins) I bought some thick ones and butterflied the one for the wife an girls to get theirs super well done an keep mine a nice medium. I gave the girls bites of my medium steak, an their eyes lit up and now they want me to cook steak like that all the time.