working with difficult bosses

Why is it that some employers of labour are taking advantage of their worker, damming any consequences that may occur?
the answer is that the job market is fully staturated and with fewer oppurtunities, not with standing, these are few points on how to deal with difficult bosses

first, know your job discriptions and do them effectively then you will not give them the avenue to question your performance.

secondly, learn how to be your own person at all time so that you are not regarded as push around.

Thirdly, when pressed with over work, ask to be relieve of some resonsibilities politey but with confidence,with that you make fewer mistakes and keep yur head above waters.

I enjoy the house discussion& welcome any comment and suggestions on this topic
cheers