I've played a fair few game like this in the past. Your version is fairly good.
Just some information:
1. The days maybe could be a little longer
2. The customers I feel take too long to be unhappy - I served 6 in the first day.
3. Some form of high score submission would be great.
Overall it's not too bad but a re-hash of many similar games. P.S Do you have a tutorial to how you made the game?