I like to occasionally use Autofill to fill in forms like for my address and email. However, it is too aggressive and overwrites things I have already entered. I don't want autofill to change the answers in fields I have already filled out. For example, I enter a friend's address in a form who I want to send something to. At the bottom of the form it asks for my address as the sender. If I choose the Firefox autofill address it goes through the whole form and enters my saved address over the recipients name and address I already entered. Great, now I have to refill the entire form as there is no way to undo this either.