There are plenty of gaps in traffic here. Actually not all that crowded compared to the East coast cities that I just drove through. I'm going to be the contrarian here and say that it annoys the schit out of me when someone is drenching me through my open sunroof w/ their windshield washers. It just falls into the general category of being completely oblivious behind the wheel, not that different from cell phone talking midget women rolling through crosswalks.
Simply adjust the squirters, unless you are trying to be generous and wash the other guy's windows too.
Seriously, next time it might be some spring-loaded ass whole who goes Medieval on your ass. Granted, in the big scheme of things it's insignificant. But most of the things that start fights between strangers are not exactly of international importance.