Quicksilver

Raised as a usability problem by 6 people on Hacker News over 5 years (2008–2012), in 6 threads.

People raised many different problems with Quicksilver, but no single problem has yet been raised by 3 people in 3 different months and threads.

Unreviewed issues were grouped by machine: Claude Haiku labelled each comment as a usability complaint, named what it's about and summed up the problem in a line, and a small model grouped similar problems. Nobody has checked them by hand. Expect mistakes.

The newest 6 complaints

Shortcut always brings up the first Emacs instance, can't switch between them2012-06-03
Can't find the download link on the page2011-04-19
UI fails when defining the action for custom triggers on Snow Leopard2011-03-15
Can't predict which result a keypress will select, so must look at screen2011-01-28
Feels unbearably slow to use and bloated2009-05-17
Simple tasks like opening a new window and ssh are frustrating to script2008-12-09