Because I reckon it must be some form of magic.
My DD really was not into writing or learning letters etc. before she started school. I would read to her a lot, but she'd get annoyed if I took it further. She absolutely hates getting things wrong or admitting she doesn't know something (must get that from her dad 
), so all I could do was try and sneak some stuff in during our normal day and hope it had some effect.
She liked maths and would randomly come out with sums but again, would hate when I'd try doing maths games with blocks or whatever.
I'm a young single mum and her dad is in prison, so it was especially important to me to do what I could to encourage her down a different path than mine or (especially) his.
We're a month in and she's just read her reading book (after a few goes with me) independently, she can write her name and she wrote 'cat' and 'mum' today, she's in her bed next to me now and she can't sleep as she's too excited that she now knows subtraction and wants to tell me every sum in the world
All this in a month! With 29 other kids to teach and her teacher and TA have managed to instil this sudden massive love for learning into her. I've been trying to do it for years, and I never managed it even though it's just me and her! I can't get over it.
I love to learn too; currently doing a full time masters whilst juggling a full time job and raising her alone - but I absolutely love learning and always have, and it was the one thing I hope she'd inherit from me.
She absolutely worships the ground they walk on too, and is so much happier than she ever was at nursery.
I read a lot of negative posts on here re teachers, and a lot from fed up teachers who clearly aren't appreciated as much as they should be - and I just wanted to say (and I'll be saying it to DDs teacher at parents evening next week) that I think you are absolute magicians and unsung heroes. Thank you for all that you do 