[nitrogen]

You'd be surprised how willing most people are to just rewrite or delete history as it suits them.

I've heard of guys whose ex-girlfriends tore out and destroyed pages of their diaries related to the guy when they broke up.

People delete their half of conversations on forums, Facebook, etc. when they get proven wrong, so it looks like the other party was just talking to themselves.

Someone once asked me to help them remove someone from a photo (not a family photo, a documentary photo of a community activity). "Why?" "Because he was being annoying!" "But this photo could be printed in the paper. He was there. You can't just rewrite history like that!" "It's my photo! If you won't help me, I'll get someone else to do it."

Rewriting history is the norm. Most people haven't read 1984, and I suspect that many that do, don't get it.