I was locked out of my Minecraft account for most of a year, because I made the mistake of making it with my middle school email address, since it was the only email I had at that point. I played the demo a lot, on an account I made with my personal email address, but that just isn't the same. I missed my old worlds. I missed my old skin. 

I did not forget my password. I know I did not, because I remember it still. But it stopped working somehow. 

And I could not change the password because I had lost access to my school email after graduating, and hadn't known to set up security questions on my Minecraft account as an alternative. 

But a miracle happened yesterday. I am able to access my old school email again, without it glitching too badly, and so I was able to reset my password. 

And I can play in my old worlds again. I had at least 20 of them. I haven't gone through all of them yet, but I have a lot of great memories rushing back of the ones I have.