Why does Gmail automatically format my text in an email when I don't want it to?

I just replied to a very important email that was sent to me. All I needed to do was reply with my name, cell number, and a list of other things that I agreed to. However when I look at the email I sent, Google automatically formatted my text as if it was a signature and made the text all gray. It really pisses me off because now I don't know if that's how the recipient will see it (they don't have gmail). Or, they might be confused and not see anything at all. And if I resend it they might think I'm retarded and don't know how to use email or something. Why the f'k does google do this??