Last week they left a bag of soiled kitty litter on their front step (which is about 3 feet from our front step).
This week there is some smeared, raw, leftover sushi all over the place. I looks like some wild animal was drawn up the three flights of stairs and they've torn into it. It's just gross.
This morning I noticed that instead of cleaning up the sickening mess, they've just tossed the free phone book on top of it, a la Adam Sandler's newspaper solution in Big Daddy.
UPDATE I came home from work and this is what I saw: