Hey Blanchflower!
Some of the service NPCs are just really, really bad at their jobs. If I recall, I've even read a tip while the town load screen is running saying something like "Keep a close eye on Sims you hire over the phone, they might not always do a good job!" (or something like that).
I recall a while back I hired a baby sitter that only watched TV, I can't recall her ever paying attention to the two toddlers she was supposed to be watching. My Sim would return from work with two toddlers in "hygiene crisis" (that's a great way of saying with a diaper full of "poo," huh?) and hungry as all get-out.
Once I hired a "Repairman" who proceeded to electrocute himself twice fixing a TV, as well!
I think maybe one out of four service NPCs are created by the game are just cruddy at what they do. There's an option to "fire" them, I think that's the only way to "punish" them.
@ Saltypaws, I had a mailman once who tossed ALL mail on the ground. He'd show up in the mid-morning, curse and stomp at the house, toss the mail on the ground in a huff, and kick over the trashcan. It was funny the first few times he did it (he always had that "Don't Like Sim" icon in his thought bubble), but then it got to be a bit annoying. I tried socializing and becoming friends with him, but even that didn't make a difference.
My Sim "fired / dismissed" him the next, and he moaned and wailed and hugged my Sim crying. I thought the game'd regenerated a new mail carrier; but the next morning there he was ... he just never threw the mail on the ground again in a huff nor kicked the trashcan.
-- Happytime