AHA, but I have already determined that cheese is not a suitable condiment for purposes of this conversation, therefore the rules of a hamburger-cheeseburger distinction shall not extend to any other commonalities when discussing topping. Sandwiches in particular are their own definitional nightmare, but I say for the sake of argument a condiment should be limited to seasonings, sauces, dips, and things that people can (should) unanimously agree are delicious toppings for a wide variety of foods, such as pickles, jams, and syrups. Oils may count too, olive oil with parmesean on fresh bread is wonderful.