One of my hobbies is writing; maybe your hobby is too? I like to keep Wiktionary open and use online thesaurus. Also, I will ask any friend to rephrase a cliche. For instance "avoid cliches like the plague". I switch this way. Plague caused death. Cliches are therefore death. "Another cliche would be the death of me" or "If i have to write another cliche, I would die." . Dramatic language, but it's different. I disagree that it's instinct, but when we hear something used frequently, it becomes habit. Some self-imposed improvisation will help you. The new shoes hurt. Can't say the word hurt. The new shoes feel like walking on broken sticks. feel like ants biting my feet. Perhaps a word war with new friends can help. It leads to discussion of writing small things, without revealing your whole work.

The only reason to explain why we use these cliches or the expressions would be we still have a limited vocabulary, we have to admit that how many words we know is one thing, how many words we can use appropriately is another kettle of fish. To play it safe, we would use the words, the cliches that we are very familiar in emails at work, however as we improve our English language skill, we will definitely try more colorful,accurate, idiomatic words in our writing or daily conversation. We still have a long way to go......no end in sight......