Every other year or so I feel the need to clean up my Debian system and remove the installed packages I'm not interested in anymore. I remember there was a nice aptitude pattern to search for packages which I have manually installed (i.e. which were not installed to satisfy a dependency). Ideally I would then go through the (presumably short) list of packages and remove the ones I don't need any more.
Since I always forget the aptitude pattern to search for those packages,
I google for something like "list of manually installed packages" and
find a solution like:
aptitude search ‘~i !~M’. Although this solution
is not wrong, it is not quite what I was looking for. Sure, it will find
you all packages which are installed and not installed to satisfy a
dependency, but it also contains packages of priorities: required,
important and ...