You'll downvote me for this but Libreoffice is missing the key feature of having everything I need in the same menu location that it is in Office. Yeah I know - old, stuck in my ways .. . etc etc
I seem to recall it all moved around in Office about 10 years ago. I still haven't got used to that, but LibreOffice menus actually seem more sensibly ordered than that stupid Ribbon thing.
(Seriously, I'm against capital punishment, but in the case of the inventor of the "ribbon" I'd happily make an exception)