Had a friend who always carried instant coffee into a restaurant. He would order coffee, then add a spoonful of instant and stir.
In a chem lab down the hall from where I used to work, they made their own instant. Coffee went into a large glass container filled with water, which was boiled down to a thick syrup. A spoonful of this was put in a beaker and boiling water added. About as bad as it sounds.
My recipe for instant- brew a large pot, enough for the day. Pour a cup anytime and nuke it in the microwave to get it hot again. Takes 100 seconds from cold to hot.