I think this is often what amnesia is so common in fiction, too, despite being extremely rare in the real world. It provides a convenient plot device, both to perform exposition and for some inevitable gotcha behind either their identity, how they lost their memory, or some other major revelation from their past (seriously, has there ever been a case of amnesia in fiction where they didn’t conveniently forget some big, plot relevant thing?).

K3s? What did you do to the other 5 letters??