Are we driven by metaphor?

I think many of our attitudes to life's problems are driven too strongly by metaphor. A very pervasive picture of human behaviour is to see us as some kind of pressure vessel which, if not allowed to "let off steam", could "explode" catastrophically. This picture probably exists because it works in many circumstances. Anyone who has had to look after children over several rainy days in the holidays would probably agree! And then we use the metaphor to argue against harbouring resentment; problems should be "let out" so that they do not "build up". I am not an expert, but this approach seems to be at the heart of our Western middle-class therapy culture. Of course it works in many cases, but the danger is to argue from the metaphor. I think C.S. Lewis said of allegories something to the effect that they should be used to inspire and illuminate, but not squeezed too dry (much like the metaphor I have just used). Could it be that sometimes resentment or grudges can just fizzle out or be over-ridden by later concerns? Our desire to dredge them up (another metaphor) could one day be seen as unscientific as the old practice of blood-letting to rid the body of disease.