What does the proverb The shallow teapot does the most spouting and boils dry most quickly means?

A shallow teapot has a larger surface and when it comes in contact with a heat source it will heat the water more rapidly and will come to a boil much sooner. Thus, it will spout hot steam sooner and it will expel the contents sooner than a deeper teapot.

It means that someone who is quick to anger will rant and roar taking an opposite position on a question, but will soon run out of debating points to refute an argument; whereas a more reflective person will listen to an argument and ponder a debater's argument in order to more effectively formulate his rebuttal.