Right?? I'm not making excuses for myself - because if I had just read the goddamn owner's manual this wouldn't have happened - but both lids are blue, and they're right beside each other. I was doing it in my garage where it was poorly lit, so I just saw the coolant tank and said to myself "Well that looks like it has some kind of fluid in it, must be it!"...ignoring my own brain's warning thought that also said "But that fluid is pink, pretty sure windshield fluid isn't pink...", also ignoring the other thought that said "There's some kind of engraved image on that other blue cap, maybe you should see what that is first?"
Total bullshit. Fucking Germans. Clearly they assume people who drive their cars are intelligent enough to figure out the difference between a coolant tank and a windshield fluid tank. Pfffft.