The scourge of the sponge

What are your pet peeves for house cleaning? There are SO many to choose from.  I didn’t know I had one until I started cleaning for others (including my husband’s bathroom) and found a sponge in one condition or another either on the sink or nearby. It appears that these are used to clean the bathroom or kitchen, presumably the sink or maybe the dishes. Sometimes people use them like a soap dish which really raises suspicion. Have they left it there from cleaning? Does it have grease residue from dishes or pots? Do they wash themselves with it?  The problem I have with sponges is