My vote went to the quote #3 (although I hesitated over #2 and #3).
Why?
Because when doing seemingly small changes, they can make quite a surprise soon after (or even worse, after a longer period of time, after an IPL as airgas2000 mentioned, when you forget about that "small" change).
My addition to the voted quote is:
There are people who make backups and those who will make backups.