I'm not so sure about that. Almost every time I update IDEA I get an annoying bug. For example, on last major update something broke and dialogs/popups wouldn't display. I couldn't close the editor because of this. When I tried to close the windows a confirmation popup should show up, but due to the bug nothing was happening. To me, being able to close an application without having to kill the process seems like a critical feature, yet it somehow was not noticed during testing.

What I'm trying to say is that if you're serious about finding issues no project/product is safe from you :)