The old couple on the Wednesday round who insist on bringing their recycling out in their hands, instead of just leaving it out on the doorstep in the bags we provide like everyone else. Because they always do it when you're in the middle of sorting another boxful out, and you have to stop and take the stuff off them. And they miss us most weeks, and then say things like "You didn't come last week", as if it's our fault they weren't in at the precise time we turned up.
Also, in a Venn diagram way, because that old couple do this, but aren't the only people who do, people who hand you a pile of eg newspapers, and say "These are newspapers". Like we might not be sure after 3 years in the job....