I think format is secondary - it's the content!
But presenting things nicely is also a form of politeness, I think, and a form of respect when it means playing by the rules of a trade or group. In terms of screenwriting you can easily go insane when you try to track down the right format for your script. And the industry is known for being picky in terms of formatting. Anyway, here are some links I recently found that help you get started:
and if you still haven't enough: 155 tips of formatting a screenplay