[hollerith]

The features that make Emacs self-documenting are superbly done.

I wish other software systems emulated them.

Another example: if you write "(funcall " (or if the insertion point happens to be an existing call to "funcall") and then hit C-h f, Emacs prompts you with "Describe function (default funcall)". If "funcall" is the function you wanted documentation about, you do not have to write out "funcall" again -- you just hit enter at the prompt.