The opening sequence and first 10 or so hours is up there.
I enjoyed the adapting enemies and the sandbox setting, base management was good too, special staff were good craic to find as well.
I was a bit burned out with that and the fulcon after peacewalker though. I also played Ground Zeroes too much, was already a bit sick of the gameplay, gets repetitive at times and a grind. Story dips as well, I didn't like quiet either, stupid character.
The first reboot and Snake eater are the best in my opinion, even if they are dated, Phantom pain was missing something for me.
But you are making me want to play it again now with your indignation, still have a few things left to do.