When you pick a job, think ahead, if you can do it properly whole time. When playing Fast Food Rush I came to conclusion, that to work in a fast food chain is totally unsuitable for me. I could not stand the pace and many customers needs were ignored. Sometimes it is simple, like a coke, or ketchup, however when you do a complete menu, you may feel sweating. Try it for yourself. Be prepared for glares from unsatisfied customers, who doesn't love to wait too long.
For successful orders you get paid properly and if you make a day limit, then off you go to higher level.