"A truly happy person does not allow his happiness to be dependent on any external factor over which he may not have control." (Chochmah Umussar, vol.2, pp.331-2)

Base your happiness on your own attitudes, and you can be its master. If you tell yourself that you can only be happy if others do or say what you wish, your happiness is under the control of those people. You can never have a guarantee how others will behave. Even when they do behave as you wish, you are likely to feel uneasy about how they might behave in the future.