It always seems that when I talk to Siri I forget what I'm saying halfway through. Siri detects a pause and assumes I'm finished. New in iOS 7.1, you can now press and hold the home button, talk at whatever pace you wish, and then release the home button when you are finished. Siri will keep waiting while you find your words.
iOS 7.1 cured Siri's impatience: Press, hold, talk, release
