I was sitting in traffic today and as I was sitting and pondering, the car door in front of me opened and the driver bent over and released a globule of spit onto the tarmac.
When traffic started moving again, I just could not get myself to drive my car over this ball of spit. So I changed lanes, in heavy traffic mind you, in order to avoid the spit, thereby creating a minor traffic backup behind me in the process.
I am not sure why I didn't want to drive over the spit. I have driven over other nasty stuff such as dead squirrels, deer body parts, horse manure and so on. But I just didn't feel like getting that spit on my wheels.