Why the small thing gets the big reaction
Answer it in your head first.
A man loses his temper about a cupboard door being left open, and afterwards he cannot explain why that of all things. What is a likely account?
The cupboard is rarely the subject. Underneath it there is usually something older running, most often feeling unimportant, unheard, or not taken seriously in the house. The size of the reaction is a clue about the size of the thing underneath rather than about the size of the trigger.