I believe people have thresholds for rage which are genetically inherited. So some people can cope easier with frustration than others before they act out. (excuse my poor explanation here, but I just want to make what I think understandable :D) I also believe that everyone has say a bank of frustration/aggression which fills up. This can fill really quickly if loads of frustrating things happens in a short period of time which’ll cause the person to act out and perhaps commit aggressive acts such as violence (at least verbal perhaps). It also can decay over time so if only a few frustrating things happens over a month you are less likely to act out. This links with the first point I mentioned, where you reach a threshold which causes you acting out. Other factors such as context cannot ever be ignored though: such as weather (lol but yes), who the aggression is faced at (eg if there has been a long history with the person), stress etc. My reasons for these views stems from personal observation, introspection, and education in psychology.