I loathe the expression "what makes him tick." It is the American mind, looking for simple and singular solution, that uses the foolish expression. A person not only ticks, he also chimes and strikes the hour, falls and breaks and has to be put together again, and sometime stops like an electric clock in a thunderstorm.

-James Thurber

I don't wholly agree with this quote, I just like the way it acknowledges the complexities involved in being a person.