I have a thing for notebooks, planners and to-do lists. I like to collect them, write in them and keep them on my shelves. It makes me happy to keep all those memories in each notebook and be able to go through it any time I want.
Also, using pen and paper automatically sets my brain in a focused mode! I don't know why, but it does!
When I write things down, I put my head in order and it makes me more productive.