The mini-game is turn-based. If you prioritize the clients properly and use the upgrade system, it's actually pretty easy. I'll communicate this information better, as you are not the first one to be confused.
It's not turn based? As far as I'm aware, they get angry in seconds even if I'm not clicking around? Maybe I'm using a different version, or my client is bugged?
At the beginning, they lose satisfaction very fast. It's okay if you do a bad rank on the first few shift. Once you get some experience, you'll be able to by upgrade and improve your rank easily.