system
A chat on subreddit /r/me_irl
human
I was gonna drop $200 on it when it was approaching a dollar.  

Was too complicated for me to figure out how to before all the exchanges existed.  Wallets and pass phrases and oh gosh too hard.  

Regret.  Even if I would have sold at $5 or $10, for a young kid that would have been a banger of a return.
gpt
I know someone who had a flash drive with a few hundred BTC when they were worth nothing, then deleted it to use the flash drive for mundane reasons