When people are eating something or drinking something and they'll only leave a little bit left specifically so they won't have to get a new one like if they just ate the entire thing
Or when people finish something, but instead of throwing out the bag or bottle or whatever they just leave it behind on the table because they're too lazy to walk a couple feet and throw it in the garbage. When people leave freaking hair in the sink. You can see that you left it there, you know people don't like that, so why don't you clean it up?
