In Jira if you close an issue you can no longer edit it; that makes perfect sense. However, you also can't add labels to it, which makes it impossible to any kind of analysis of tickets after the fact (eg. to label the bugs found in productions differently from bugs found by QA). Furthermore, even if the issue isn't closed, you have to go in to the issue, and then open a drop-down just to add a label.

It'd be great if:
A) you could add labels to closed issues (or at least make it an option)
B) add labels more easily on the issue page, without needing the drop-down
C) add labels from the issue list page