Why is it not acceptable to urinate in the sink?

I lived by myself for a long time and I got into the habit of peeing in the kitchen sink cause I would be watching TV or getting beer or just hanging out with my friends and it was always easier to just whip it out and siphon the python right there than go all the way to the bathroom. Well last night I was at a friend of a friends house and we were all in the living room having a great time watching a movie on TV and I got up to get another beer out of the refrigerator and before I even thought twice about it I unzipped my paints, whipped out the old german soldier and drained the lizard right there in the kitchen sink. OK, so that pretty much ended the evening when the wife of the guy's house we were at had a hissy-fit and demanded I leave (and never come back, I might add). The sink drains into the sewer, doesn't it? I'll bet people in europe wouldn't think this was a big deal, and I really didn't mean to cause a scene. Why do you think she went so postal and poured a gallon of bleach in the sink and was screaming at her husband and all? Was I really THAT wrong?