There are a lot of situations in life when we have to control our emotions. We have to be polite no matter what we feel at the moment. Especially it concerns relationships with your boss and colleagues.
There are cases when you think that too many duties are laid on you and it is not fair. Everytime you should be careful about the things you say at your workplace not to damage the relationships.
You should be careful when speaking about your wages and advancement. If you are asked to do something but you feel that you don't have enough time for that don't say that it's not your job. Don't promise but say that you will try.
Never blame others for something wrong. You will be considered a finger-pointing person but not a problem solving one.
So managing good relations is not an easy matter but still it is possible.