I took over a Sim and added to household trying to figure out what inspirational speech did and saw no moodlet, but when I brought the Sim under my control I saw that she was uncomfortable and it was obviously going to impact her work. This was a chef so not a Sim you want cranky if you want good service. They do seem to come in with high or reasonably high needs, so you can expect theirs to fall at about the same rate as your Sim's. Allow for a margin of error and observe them and you can just close before this message even comes up, probably avoiding them growing dissatisfied. It's hard to repair that, and you can only give so many raises of course but it may pick up over time. They do not seem to need much time in between openings to recover from work.