I go to quit emacs, or kill a buffer. It has been modified. How can I see what the changes are? An ediff for this would be nice.
You know what would be great? If when asking whether to save the buffer, emacs would offer to show the diff.
I like your suggestion.
What I do is "undo" which tends to remind me what / where the buffer got
changed. Often it was by accident. And if I want to keep the changes, I redo and then save.