Not The Muffler
This one is quick, and also automotive in nature.
Years ago, a customer pulls into the garage. It was our only customer that week.
Our mechanics Manny and Ralph are standing next to each other when this car pulls in. The car sounds terrible. Loud rough engine sounds. Obviously it's got exhaust system problems.
The customer gets out of the car and he says, "I think I need a new muffler."
And Ralph says, "Sounds like that to me."
And Manny says, "No, I don't think so. It's not the muffler. It's the front pipe."
The customer says, "No, no, no. I've been listening to it for a week. Trust me, it's the muffler."
And Ralph says, "I'd have to agree, it certainly sounds like the muffler to me."
And then Manny says, "Well, yes, it does sound like the muffler, but I know that it's not."
What did he perceive? What did he notice that these other two guys didn't notice that allowed him to figure out that it wasn't, in fact, the muffler, but it was the front pipe?