It’s not hard to imagine.
For anything to burn, it has to have fuel. After all, it’s a chemical process and like algebra, there has to be something on the other side of the equation. Without a balanced equation, the results are skewed. For instance, if a fire needs oxygen to survive, why is it that a match can be squelched by a passing breeze? Why is it that human beings, who can survive only three days without water, can drown in six inches of it?
The answer is easy: too much of a good thing can kill you.
Don’t believe me? Figured you wouldn’t. Okay, students: class in session.