Wired Differently

People use the expression that they are wired differently. Why are some people easy going and other people high strung? It has to do with the electrical impulses that run through our brains. Since electric systems have wires, that statement came about. Are medications the electricians of our brains? Do they straighten the wires so the impulses flow correctly? I want to be around people who have a well built circuit board, not people who are one step away from an electrical fire.