This just happened today, but it has happened before too, and I bet I'm not the only one.
I'm in the parking lot standing next to my bike, wearing my riding jacket and taking my helmet off the seat to put it on. The person walking by asks:
"Is that bike yours?"
"You wouldn't be riding a motorcycle if you weren't an optimist."
- Matthew Crawford
2005 Ural Tourist, 2000 Kawasaki W650