The default in
dired is to mark files and folders with m, and to unmark them with u. Instead of this, I'd rather like to use shift-up and shift-down for marking or unmarking lines (in a DWIM fashion). So shift-up would mark/unmark the current line and move the cursor one line up.
This is nothing particularly fancy, I guess, and I would preferably use something already built in into
dired or provided by some extra package. But I haven't come across something like this so far.