When we are most frustrated with other people, we have a wonderful opportunity to learn something about ourselves. A disorganized staff member? An arrogant client? An unreliable colleague?
Often what we bitterly criticize in others reflects most strongly our own inner fears and doubts. And usually it is either what we most fear in ourselves (and try to stamp out by seeming to act the opposite way) or what we feel (again, motivated out of fear) that we must do most to avoid.
If, the next time you feel really angry or frustrated with someone, take a good, hard look at yourself: your attitudes, behavior, needs, fears. And try to figure out what it is that you want or need to change in yourself. Doing so may significantly reduce the frustration you are experiencing with the other person, and hence improve your relationship.