When you sleep with your beer under your pillow? And stick a nipple on one to suck on to fall asleep. What!
When you go to the hardware store for something completely unrelated to brewing and you end up wandering the aisles for half an hour looking over hardware just to see if there's anything that you need to modify your brew setup.
...when you pour a can of campbells tomato soup into a pot and leave about 1/8" in the bottom of the can.
When you start researching your next recipe while chilling the wort.
When you take a corny keg with you to go refrigerator shopping