In psychology, frustration<span> is a common </span>emotional<span> response to opposition.
Related to </span>anger<span> and </span>disappointment<span>, frustration arises from the perceived resistance to the fulfilment of an individual's </span>will<span> or goal </span><span>and is likely to increase when a will or goal is denied or blocked.
There are two types of frustration; internal and external. Internal frustration may arise from challenges in fulfilling </span>personal goals<span>, </span>desires<span>, instinctual drives and needs, or dealing with perceived </span>deficiencies<span>, such as a lack of </span>confidence<span> or </span>fear<span> of social situations. </span> Conflict<span>, such as when one has competing goals that interfere with one another, can also be an internal source of frustration and can create </span>cognitive dissonance<span>.
External causes of frustration involve conditions outside of an individual's control, such as a physical roadblock, a difficult task, or the perception of wasting time.
It shows that there was a struggle. There wouldn't be another reason for the attackers skin cells to be under the victims fingernails unless something happened. Check for DNA or scratches on the attacker
