Memory is unreliable because it is shaped by more than accuracy. It is influenced by identity coherence, current emotion, later information, and the meaning your brain is trying to preserve. Someone who feels confident today may remember a more confident younger self than the evidence supports. Someone who feels anxious may over-recall anxious moments and under-recall calmer ones.

This is why personal accounts of one's own past deserve some skepticism. The speaker is not lying — but they are reporting the output of an editing process that was never built to preserve the past like a recording.