"I'm a dentist," he said, quite proud of himself, "and what do you do?"
"I do computer stuff mostly," I mumbled.
The guy -- I swear -- spent the next 5 hours of the flight telling me about how he wanted to computerize his dental office but his partner didn't understand things, how he was having problems with some software they had purchased, how he was looking to buy a new computer and didn't know what to get. For each subject, he questioned me at length for what I thought he should do.
Finally, at the end of the flight just before we got off, I opened my mouth as wide as I could and pointed to the back of my throat
"Doc," I said, "I got this sore tooth that only acts up when I eat ice cream, but sometimes the gum swells so I've been using a special toothpaste. Care to take a look?"
That was the end of that.