Well this thread certainly took an interesting turn!
I throw away yucky food containers too. Sorry great-grandchildren. We also have very limited recycling here (corrugated cardboard, newspaper and aluminum cans only). So even if I did wash it out (thereby wasting potable water that we desperately need to conserve here in the desert), I'd throw it away anyway. I'm not proud of it, but I'm not going to let it keep me up at night either.
As for the actual topic of this thread. I'm like most everyone else. Messy is no big deal, but dirty bothers me. And this thread has inspired me to sweep and mop my floors, LOL!
I have an amusing story about unexpected visitors and extremely messy houses. This was a couple years ago, DS1 had just turned two and DS2 was a newborn. The piece of @$%! washing machine that we had at the time had broken down yet again in the middle of the wash cycle. I was trying to fix it with ds2 in a wrap on my back. In the meantime, ds1 had poured an entire box of Cheerios on the floor and scattered them through the kitchen and living room. There were toys everywhere. The dirty dishes from dinner the night before were still in the sink.
I'm swearing at the washing machine, frustrated to the hilt, with a screwdriver in one hand, a wrench in the other and a baby on my back when I hear a polite tap-tap at the back door. I look up to see my MIL standing there. I'm sure the look on my face was priceless. Turned out she needed to use the bathroom. It was the one and only time she arrived unannounced. She politely and noncholantly tip-toed around the Cheerios and somehow dodged the toys. To her credit, she didn't say a word and probably would have stayed and helped me clean up if she hadn't been in a hurry.
In the moment I was so frustrated by the washing machine that I didn't have it in me to be too bothered. I was pretty mortified later though! My only consolation was that at least the bathroom was clean!