My favorite so far is the comment I got while filling my 2 1/2 gallon gas can for my mower:
"What is that, about a years supply?"
Meaning for the smart, of course.
Second favorite was the elderly gent who watched me get out one day - me, 6' tall, 290 pounds - "That would make a good advertisement for that car - big guy, like you, getting out of it~!"