Catastrophising
Terrible jargon but describes accurately what a lot of people do in relation to events that happen in their lives.
Instead of a small or appropriate reaction to something that happens to us as an everyday event the response can be totally out of proportion. We, in fact, respond as if a catastrophe had occurred and the resulting physical and mental stress can create problems to the person if this pattern is not modified.
When you are about to blow a fuse over something trivial (you've just put the washing out and it starts pouring with rain) stop for a moment and ask yourself if this is really a life-threatening event. If it isn't then don't react to it as if it were.
This is particularly relevant to situations where physical risk is involved such as over reacting to someone else's driving. Road rage is a good example of how a small event can be elevated into a catastrophe.