Why don't we have robots doing all the menial jobs?

I don't get it. Robots would be far more cheaper and efficient than hiring someone on a yearly salary in the long run. Just imagine - if we had robots in fast food chains, as office clerks, as warehouse assistants, as train drivers - the world would be so much a better place!

Robots don't complain, they don't have needs, and they don't talk back with an attitude. Robots are completely obedient. Most of all, they don't need some union to encourage protests to increase their pay every month or so to have a reason to carry on with their miserable jobs.