The Jewish people are My servants, and not servants to servants (Bava Metzia 10a).
As a host and his guest left the apartment building, the doorman greeted them in a belligerent tone of voice. The host responded in a gentle tone of voice and with a very pleasant smile.
"Is he that grouchy all the time?" the guest asked.
"Sometimes even worse," the host answered.
"Then why are you so pleasant in your response to him?" the guest asked.
"Because," the host answered, "I am not about to let him dictate how I am going to act."
If we react to others' provocation, we are essentially allowing them to control our behavior. A sign of slavery is being deprived of the ability to think for oneself, so here, if we react reflexively rather than rationally, we are at least temporarily in involuntary servitude. How foolish to allow ourselves to become enslaved, even momentarily.
The antidote is to avoid reflex reactions. We can make it a point never to respond when provoked until we have stopped and allowed ourselves ample time to think rationally about what has happened and to plan what would be a rational, well-calculated response.
One might think that delaying a response to provocation is out of consideration for the other person, to protect others from one's own wrath. This is true, but secondary. The primary reason is that we maintain our own freedom and do not become puppets manipulated by others.