My favorite is when they do the "splash bath" in the lavatory. I was on a BRU-JFK flight a couple of years ago, and I went to the lav just after take-off (and I saw who came out of that lav just before take-off). When I opened the door and looked inside, there was water everywhere. The FA was there in the galley, and I said to her "what the ...??" pointing to inside. And she rolled her eyes, saying that it happens quite often on this route. Too bad there isn't a direct flight from Antwerp to JFK so I can avoid this on my flights out of BRU. Or at least make the sign in the lav in bigger letters asking people to wipe-off the sink area for the next passenger.