Temporary reduction to your Intelligence Score

It's like this, if you want to be an Orc then you exchange Intelligence for that extra Strength. If you want to be a Bus Driver you also lose Intelligence. I can prove this. Let's say a scruffy looking, bearded, old guy limps up to the bus you are driving and after staring at the sign that says Oroville for a miunte and a half asks, "Does this bus go to Oroville?" - how do you respond? All you Bus Drivers out there probably said something like, "That's what the sign says.", but a smart person would have said, "No." And now this toothless vagabond is standing on the sidewalk staring at you, patiently waiting for about 1.3 seconds before he snorts out, "Well ain't you gonna drop the lift? Ya watched me gimp up here." That illiterate old fart just insinuated that the Bus Driver is an unobservant cretin, and the rest of the passengers are nodding their agreement. Once the brain-draining deviant is on the bus he will invariably sit in The Stupid Seat. For all you non-Bus Drivers out there, this is the seat closest to the driver, with a full view of the road and everything the driver does, it is the domain of the Intelligence Leech. He will such IQ points as fast as the odometer counts off miles. But this is an exchange, so what do you get in return for the lost Intelligence? Well... Um, I think it had something to do with... aw, shucks. Uh, if I remember, I promise to tell all y'all what it were.