"You love doing that"
BYU has (or used to have) a lovely program where students could have their taxes prepared for free by students in the accounting department. (You get free tax advice, they get lots of practice, everybody wins.)
One year I decided to take advantage of this service, so I signed up and showed up in the Tanner Building at the appointed day and hour. I waited for about half an hour with maybe a dozen other people, when a student came in and said "Just so you know, all of the students in Accounting XYZ had a big test today, so some of them may be late for their assigned times in the lab." Of course, you can't look a gift accountant in the mouth, so I decided to wait it out.
Sure enough, at about 20 minutes after the hour, a flustered looking girl came in, sat down, and called the next person up to be helped. She called me up after that, and as I was pulling out my forms I casually said: "How was your test."
She STARED at me.
After a few seconds, she finally said "Do I know you?"
I laughed and explained that someone else had said the students in some class had a big test today, and she'd come in late, so I put 2 and 2 together.
Later, I retold the story to Melyngoch adding (ever so modestly), "It was a perfectly logical conclusion, you know."
"Don't give me that," she retorted, "You LOVE doing that - pulling something like that out of nowhere and baffling people."
OK, I admit it. I do love doing that.