Like many other essays of Paul Graham, this one is a pretty good one, even though it's only his idea about speaking and writing:
If you have ever listened any of Paul's talk you will see the essay explained a lot about that. It's because he's using his pre-written scripts when talking. But after all they are really good ones. It's really hard to be a good speaker. It is a trade-off. You have to be a bullshitter just like Paul said. Indeed, sometime you have to talk about things that you don't even care to get the attention of the audience. I don't like that.
After a while, I figured out that it doesn't matter that people will like your talk, the idea that you're trying give is matter. So, I quited being a good speaker and trying to be a good thinker and writer. I'm practicing my talk (whenever I have a chance) by writing it down somewhere, repeated it many time. I know it will not be a good show but at least I will say what I really mean. Talk slowly and think carefully.
I agreed with Paul and chose to act like that. Time will answer.