Martin Amis on avoiding the cliché
Cliché is herd thinking, herd writing. —Martin Amis
That gets at one of the core reasons why clichés ought to be avoided. Clichés are tribal. They're stand-ins and ciphers for actual feeling, actual experience. They're catch-phrases or pat answers. Some are more annoying than others.
Not that all of writing consists of avoiding clichés; or that one needs to think about clichés when writing. That's only likely to create problems, since you are drawn to whatever it is you're avoiding thinking about. But when a cliché does come up, it's easier to spot if you look at it in context. One definition of a cliché, of course, is that it's a stock phrase or image that one has already encountered numerous times in literature, and poetry. It's a too-familiar phrase, especially in context.
Clichés are thoughtless. They don't take any work. You can drop them in and avoid doing the hard work of actual description. They are a way of avoiding the real work of writing. When a sign or a symbol or a cipher comes too readily to hand, too easily slots in as a descriptor, it's probably a cliché. When one is too lazy to evoke in the reader an experience or mood, clichés abound, because the reader is supposed to know what to feel when they see a given cliché. It's worked before, ennit? The problem is, yes, it's worked before, but that was many times ago. The lazy writer manipulates. The writer who actually puts a little effort into writing finds ways to evoke that are not blatant manipulation.
Not that all of writing is about being original or fresh. Sometimes you want to evoke a stale and musty mood by using stale and musty language. But you can do that and still subvert the clichés that go along with stale and musty moods and scenes.