Simile and metaphor require just as much precision as literal language. (I’m tempted to say they require more precision.) Figurative language isn’t a hiatus from verbal rigor. I will grant that when you put different writers’ similes next to one another, you can get the impression that anything goes. Robert Burns says “My love is like a red, red rose.” Sir Philip Sidney says “My love is like to ice and I to fire.” I might say my love is like a summer’s day. Or I might say my love is like a hurricane. So which is it? you might ask.
Well, if you have ever loved anybody for any length of time, you already know that your love is sometimes like a red, red rose, sometimes like to ice, sometimes like a summer’s day, sometimes like a hurricane, and at other times like any number of other things. (I recently saw something thing that said, “My love is like a candle: forget about me, and I will burn your house down.”)
If I say, “My love is like a hurricane,” in one sense I am broadening the reader’s conception of what love (or, perhaps, a lover) is like. But in another, very important sense, I am focusing and narrowing the reader’s attention on one particular aspect of what it is like to love another person.