What do metaphors and similes do?
If the plot and characters in a story are the meat and two veg on the plate, the use of metaphors and similes are the sauce and seasoning. They give a story its flavouring. To use a simile I have employed elsewhere, they are like the music track to a film. They provide a background that enhances the mood. They describe emotions and feeling that lie beyond the boundaries of language. They create a unique ambience.
They are best illustrated with examples:
'I felt like a soldier trying to sleep in the trenches the night before a major battle. And that wasn't so far off. In Kabul, fighting kites was a little like going to war.'
The Kite Runner, Khaled Hosseini.
Thus the simile proves an interruption rather than an illumination.
The Kite Runner is Hossseini's first published work and, despite the fact I thoroughly enjoyed the book, it is evidently a beginner's book, full of the tricks of the trade taught on creative writing courses and so lacks the authority of one who is fully confident of his voice. And one of the indications of this in any new author's writing is the overuse and misuse of metaphors and similes.
To give another instance, I looked through Disgrace by J. M. Coetzee, winner of the Nobel Prize for Literature in 2003, and could not find a single example of either a simile or metaphor. (I only skimmed, so they may exist.) He reports what he sees and allows the situation and dialogue to create the image. This is not say that these tropes don't have their place but the sensible writer is wary of them.
Chocolat is Joanne Harris's third novel and, though I find her overfond of comparing things to things, her use invariably illuminates:
'The carnival is gone. Once a year the village flares into transient brightness but even now the warmth has faded, the crowd dispersed. The vendors pack up their hotplates and awnings, the children discard their costumes and party-favours. A slight air embarrassment prevails, of abashment at this excess of noise and colour. Like rain in midsummer it evaporates, runs into the cracked earth and through the parched stones, leaving barely a trace.'
If you have any examples of suitable or unsuitable metaphors or similies, do let me know. Similarly, if you have any observations or queries.