The curse-ed ribbon was a huge productivity regression. I still use very old versions of Word and Excel (the latter at least until the odd spreadsheet exceeds size limits) because they're simply better than the newer drivel. Efficient UI, proper keyboard shortcuts with unintrusive habbit-reinforcing hints, better performance, not trying to siphon all my files up to their retarded cloud. There is almost nothing I miss in terms of newer features from later versions.