>The very worst IMO, at least of the ones I have run into, is Excel 2007. I don't use Excel very often and every time I do it is an exercise in "Where did they hide this command?"

I have been so annoyed with Excel 2007 (and, to some extent, Word too) that after a couple of years I simply gave up on Office 2007 altogether and, when one of those "oh crap I have to reinstall everything" I went back to 2003. After yet another one, I didn't even bother with that. For what little I need, I use LibreOffice.