A certain someone mentioned in a previous article that you can turn on a preference in Mac Mail that'll only include the text you select from a message when you're replying to it or forwarding it.
And if you're not using that tip, you should be, because it makes things SO much easier than trying to delete unnecessary text afterward in the message you're composing. But did you know you can do this on your iOS device, too? And you don't even have to adjust any preferences! It's easy. Just like on your Mac, you'll select some text from an email before you hit Reply or Forward. To do that, touch and hold briefly on the message body until a word is highlighted, and then drag the blue “handlebars” around until you've got your selection properly marked.
After that, hit the arrow button to reply to or forward the message…
…and only the previously selected text will be included in your new email.
Coolness! I find this even more useful on my iPhone than on my Mac, because to me, it's much simpler to just pick the darned selection ahead of time rather than editing afterward. No, Aunt Millie, I don't need to forward your unfunny jokes along with the directions to the family reunion this weekend. It just makes us all look bad.