I am a user of Jira because I use IntelliJ Jira (3.10 Enterprise b#260).
Overall, Jira's Web UI is really great, but one really bad performance problem is on the Watches page
(URL like this http://jira.atlassian.com/secure/UserWatches!default.jspa)
I have watches on 100s of issues. When I want to clean this up by unwatching the issues that are fixed,
if I click 'Unwatch' on that page, what it does is reload the entire page.
It would be nicer if I cloud click a number of this 'Unwatch' links and Jira would use AJAX to notify the server and then update the status inline without reloading the entire page. Reloading the entire page is taking a long time (20 seconds).