Many people who get into public speaking think that they need to be impressive all the time or no one will listen to them at all. They want to use big words and complex thoughts to get the point across. But this does not work all the time. It can make it hard for the audience to figure out what is being said and may ruin the message. Plus, when you are trying to be impressive, rather than focusing on the message at hand, you may get in over your head, which will make you more nervous than before.