[Lawtan]

For me (I dislike amnesia plots as well)...it is largely because it is done more as a trope than as an explored mental phenomenon. Give the characters extreme fear and anxiety - they've lost part of what makes them...them. It is incredibly stressful to forget a part of your self. Depression can do this, as well as trauma or stroke or dementia...and as memory is sort of your brain telling your story to itself, even if recovered there can be a sense of disconnect - of you in your memory not being you.

>.> I'll know MonBon won't like my stories, then. About half involve some form of saving a world or town or group of people. <.<