Writing Backstory and Writing Information

When you read a book it's completely different from watching a movie. The common line in we writers are taught (and authors preach) is to "Show it, don't tell it" which, if you think about it, is completely and utterly ridiculous simply because it doesn't actually make much sense.

Okay, okay, I get it, it does. And this blog post isn't actually trying to poke holes in the theory but rather to embrace it. Chat about it.

Veronica Roth, author of the Divergent series, said that if you're interested in knowing how to write a good back story, get your hands on a copy of The Maze Runner by James Dashner. Since the main character has no memory of his past you find out his past at the same time he does which means you don't feel like you're being thrown all of this information that you (the avid reader) think is useless. (Yep, authors, we think sometimes all of that super important information you wrote is useless...)
So, my thoughts today have been on the idea of how does one write back story and information without it being boring or seem like you had to squish it in somewhere? 
My conclusion? Well, I didn't really come to one but pondered on a few books I had close to mind (one being Harry Potter of course, I mean when isn't Harry Potter one of the first books that come to mind?).
I decided that a lot of books seem to have an old person or an all knowing person who has all the information and waits patiently for the protagonist to ask the right questions or be the right age to reveal something. Or the meet a family member who has the answers. All in all, there is someone who knows and we ask them questions. Sounds simple enough and it seems to work because before you know it you just read 2 pages of description that you found interesting because you connected with the main character so therefore you too want answers.

So, with this revelation, I realised I need an old person who knows all to show themselves. Great. Glad I realised this now not halfway through writing.

...I knew there was a reason I hadn't written much (errr, anything) yet.