In our last family home (dad, bro, sis, me) we were jarred awake by a phone call at 3AM one Wednesday night. My cousin and her eminently unlikable boyfriend were at the at the airport, just back from Hawaii, and completely penniless; ha-ha, can we pick them up, and since they live hundreds of miles away, feed them and put them up for a couple of nights? Never mind that I have uni classes in the morning and Dad's going to work at seven. Dad headed to the airport while I figured out what we had to make a bed from in the living room.
I was chief cook as part of my "rent" agreement, so next day (having gone out and bought extra) I was preparing a budget cut of meat when my cousin asked about it. I explained that my brother and I bought all the food, and my money was summer job savings after school costs, so learning to the make the most of cheap cuts was SOP around there.
"Oh," she chirped, "when I go shopping, I just get whatever I feel like buying!" Well, maybe if you were a little more responsible, you wouldn't go on tropical vacations without adequate money I didn't say.

So no, they didn't leave crap on the walls or honk in the waste basket, they just called at an ungodly hour and freeloaded for two days because they weren't mature enough to travel responsibly, and then lorded over their spending habits to me. Years later, we happened to get together, and she said "It's so good to see you again. I don't know why we drifted apart when we used to be good friends!" I knew...