Be Concise
We can't understand complex ideas and people have short attention spans. People aren't listening or reading closely; they are preparing what they are about to say. We also have the ?Illusion of transparency — the belief that we convey our ideas more clearly than we really do.
You must be concise to convey meaning effectively to others. People won't give you the time or attention necessary to understand you if you don't make it easy for them. You don't keep reading a bad writer and give him the benefit of the doubt to better understand him. You move on because you're confused or bored. If there's anything you want to accomplish through working with or helping others it will start with communicating effectively: Why I Write.
Brevity also forces you to refine and understand your own ideas. Are you using cliches and big words to act like you know something, or can you explain it to anyone? If you can't explain it, you don't know it
TLDR:
We make less sense to others than we think we do, so be concise. No one wants to take the extra time to understand you.
References:
Writing that email to customers—carefully eliminating every unnecessary word, and reshaping every sentence to make sure it could not be misunderstood—would take me all day.
The Almanack of Naval Ravikant If you can’t explain it to a child, then you don’t know it.