My mom found my step-dad drinking just hot water one morning. The inside of the mug was the same color brown as his usual coffee/milk. (Yeah, instant coffee.Yup but white on the inside so you can see the coffee lol.

"What are you doing, honey?"
"Figuring out how to build (whatever he was working on)." Sip.
"How's it going?"
"Fine." Sip.
"How's your coffee?"
"Fine." Sip.
"Honey, you're drinking hot water. You never put the coffee in there!"
(Surprised look) "Why, so I am!"
A good story and memory.