It's funny how real amnesia is incredibly rare, and if you have it, it's probably a sign of much worse brain damage, but it's incredibly common in fiction, and those who have it are usually just fine other than not remembering things.
It's a killer handy narrative device though 
narrative devices been getting a little too handsy if you ask me 
I watched this video yesterday but I can’t remember it because I have amneeeeeesia
Oh really? 
I found a YouTube link in your post. Here are links to the same video on alternative frontends that protect your privacy:
I can usually remember games okay, but I played Final Fantasy VI right up to the final boss castle, and a year on the entire plot has basically escaped my brain. So I went to check my save file, which broke and neither MGBA nor VBA-M will load. FFVI removed itself from my brain wholesale.
I think Final Fantasy and JRPGs in general have a way of losing people because plot points are spread so far apart from one another. Spend a couple hours running through a dungeon and unless you're paying real close attention you might forget why you entered it in the first place.
And yet FFVI is such a drag-you-by-the-nose cutscene simulator.... I can recall more of FFIV, I dunno.
Tabletop, DnD, board games, and minecraft. Also Animal Crossing.
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