When you start refering to the garage at your house as "the VH"
When you drive by a red barn and check for GVs
and finally, when you hurt yourself in the garage you start yelling "Anyone got supplies!!"
My father has a Piper Cherokee, and we were flying over a lake a couple of days ago. I looked at him and not even thinking said "dad, look at all the PTs". His expression was:huh