We were on vacation (Rehoboth Beach, DE) in June. One morning Mike walked to the coffee shop to pick up our morning fix (two larges, black). He came back with just one cup, and when I asked him why he explained....
The coffee shop we favor has a fairly rickety screen door. It also has lots of newspaper-reading patrons propped on benches on the roomy sidewalk near the entrance.
Mike bought the coffee and stacked one cup on top of the other to navigate said rickety screen door. He made it outside, but when he let go of the door the top coffee teetered and fell, smashing in a hot liquidy burst on the sidewalk. Mike picked up the empty cup and the lid, tossed them in the trash, and turned to see many faces looking at him sympathetically. Mike, suddenly embarrassed, held up the one remaining cup.
"That's why I always buy a spare."