A family of Microsoft word processing software products for creating web, email, and print documents.
I am also an experienced and reasonably competent user and I found the learning curve from 2003 to 2007/2010 quite steep because the interface was so different (2007 and 2010 are pretty similar).
Now, half my office is on 2013. I still have 2010 but had to use another computer yesterday and found the things that things have completely changed again. I'm not talking about regular editing functions - I can figure those out - but more advanced features like custom templates that I am relying heavily on and which I have to teach to other people to use. I had built specialized Word templates and wrote a detailed job aid on how to install and use them. Now I have to rewrite the instructions completely -- but I cannot even figure out how to do it myself anymore. I have another post asking about this problem in this forum, so won't get into it here.
By the way, someone showed me how to hide the big ribbon thing (which is much bigger in 2013 than in 2010) by hitting a little arrow in the corner somewhere. I can't tell you where right now because I'm back to using 2010 on my own workstation. This is actually a pretty nice feature because you can hide/show it as needed.