One problem is, we cannot predict the future and we don't know how to do some little things. We are not sure if we are right. But when we go back the past, we will immediately know how to do things at hand (like buy BitCoins)

When it comes to BitCoins, I must summon @悄悄打开魔盒 

Yes. I think fortune cookie can play a role in helping foster one's belief or reminding people to introspect themselves.