Traditionally we use half&half (causing the rest of the world to ask for a translation; it's a thinner cream that's halfway between milk and whipping cream.) It's available in little ultrapasteurized single-servings as well as fresh.
But if keeping the dairy products refrigerated isn't convenient, there are powdered imitations that deserve the contempt you've expressed, and liquid imitations that are excuses for corn syrup and artificial flavors, and also non-dairy creamers for people who can't tolerate lactose or want something that's kosher to use at a meat meal.
My high school chemistry/physics teacher would boil water in a beaker over a bunsen burner to make his instant coffee with. The water was hard enough that the beaker had a sludge just from that.