Really excited - The laziest and least creative way to begin a sentence.
Really excited - The best possible indication that you are about to try and sell something to your readers, or you are trying to impress someone within your place of business.
When someone is obviously irritated or annoyed you can tell them ‘don’t sound so excited!’ Or maybe ‘don’t seem (or get/be) too (or so) excited!’ To piss them off or maybe make them laugh.