A) Teasing - can be quiet fun to do, and is expressed in children. Whether or not it comes from experience or instinct alone I do not know.
B) Rejection, negative-feedback - can be used as form of judging a person's behaviors or thoughts, and can work as to model the person out of or into a particular behavior. Example: You are "bad" at singing. This criticism (negative reaction) can cause the individual to remodel their behavior, stopping what was rejected and taking on another form of being. However, a person may continue in there efforts of self-actualization, even in receiving a greater "third nature" (amount) of rejection.
The reaction of negativity, to negative-feedback, greatly depends on attachment, emotion, and value. A person that neither values, or is positively attached to their behavior will not react with an emotional negativity when they are given negative-feedback. This means that negative reaction greatly depends on positive attachment. Example (induction): Think about love as an obsession to y. The more intense that love, positive attachment, the more emotional pain there will be when lost, Take the converse, when something is not even in one's life as an attachment, there is no repercussions or reactions (possible hypothesis for closed and open experimentation).
C) Emotional abuse - The intensity of a threat (see 2), can become emotional abuse. When some one is threatened with death or ends that are painful as caused by the other, this can result in emotional abuse, and obviously physical abuse if the threats are "manifested".
This according to Behaviorism is called negative-reinforcement, it is to used as "threat" or "pain" as to reduce undesired behaviors in others or self. Its a way of control or dominance, as you might find out through experimentation or description of past social experiences (positive-reinforcement is also possible).
3) Inflicting pain
Really hurting people, might be the result of what I call the elimination principle of frustration, where one becomes angry and acts to harm others as to eliminate their feelings or target.
4) Masochism and Sadism
They also may be inclined to do as not just because of the above, but also because of gaining pleasure from it. Sadistic personalities works with in these mental reactions. It can be seen in young children and developed or emergent in older humans. Pleasure derived from other's pain, also might be called deficient empathy and sympathy. The later are functional in seeing self in other, and treating them as to benefit them. Some sadism, lack of empathy, can be in one's own interest rather than others, and be easily justified and permissible both by law and will.
All threats to life cause fear unless it is inhibited. People that do risk behaviors routinely are likely to become accustom to comfortability. For example: A solider in war at first will probably feel more fear when first engaging in battle, but may become more confident dependent on experience as well as strength of his platoon.
This article frames the distinction between "pain" "threat" and "admonishment/warning".