What REALLY grinds your gears?

[over the mountain]

people who use their windshield wiper fluid on the highway. an audi got me pretty good this morning on the beltway.

im kinda torn on this. its just water/wiper fluid and unless my car was just washed i dont think it leaves any spots BUT the audi certainly has to know that he/she is going to get a good amount of spray on the car behind them and it is an unwanted offensive touching (however slight) on another persons property.

i guess the tipping point for me to not like it is that the audi had to have known but does it anyway.