I hate ketchup as a sauce or spread, don't mind it as an ingredient but it's way too fucking sweet to put on anything.
Mayonnaise for sandwiches, with mustard or horseradish.
Hot sauce for eggs, beans or French fries (chips) . The salsa yucateca if I want hot without sour, Tabasco if I want sour; hot chili garlic paste if I want flavor bomb.