I had a funny example of that.

I had a question about how to do something in Django, and after googling found a good SO answer.

I read through it thinking about how much I appreciated the author's detailed explanation and answer.

When I looked at the author it was me from two years ago.

Wow. Lucky you. When I come across code I wrote months ago, usually I'm like "what kind of crack was I on when I wrote this?"

How can I learn this skill? Past Me is usually just this idiot who made work for Present Me.

Turns out, that is also past me. In fact, often the incredible code that brilliant me wrote, which I don't understand now, is also the code that reckless me wrote that I now need to fix/add to -- and I have no idea where to start.