When editing my own question, sometimes I want to discard the change. This can be done by navigating away, but ideally there should be a place within the browseable area (e.g. a button or link near the "Save Edits" button) that allows me to go back to the original question thus discarding my changes.
In Wikipedia for example, at the bottom of the editing page there is a small "Cancel" link next to the big "Save Page" button.
I tagged this a "bug" because it seems to be a missing feature rather than a feature request.