Rule of three

Three is the smallest number that sets up a pattern and then breaks it, which is why lists of three feel finished and why jokes establish twice and pay off on the third beat. Speechwriters lean on it and comedians build whole routines on it.

It is a tool with a cost. Overused, the rhythm becomes audible, every sentence starts to sound like a speech, and readers now clock the pattern as a tell of machine-written copy. Use it where the beat genuinely helps the line, and vary your sentence shapes everywhere else.