I was going to prank him by telling him I bought a $99 purse, and wait until after I helped him down off the ceiling before I told him it was on clearance for less than $20. But when I told him I'd bought a $99 purse, he didn't even flinch. He only answered, perfectly calm and relaxed, "Well, I'm sure you didn't PAY $99 for it."
Ever have somebody not fall for a prank like that, and you think, oh darn?