Writing Needs Motivation

I sit down at my computer and stared at the screen. There are two books I'm working on plus website posts plus writing group writing topic plus book marketing plus pictures and pages for the botany project waiting for attention. And I sit there.
Why does a writer do that? I love to write. I like my different projects. Why do I stare blankly at the screen?
There seems to be two reasons. One is life in general. When the mind is too occupied with happenings and events going on around me, I find it hard to mentally walk away and into the world of a writing project.
Overcoming this takes several approaches. One is having a regular writing time. This is what I do from time x to time y. Baring total disaster, the outside world can exist without me for a couple of hours.
Next is distraction from the outside happenings. I use my Ozarks book to take my mind into another place. Once there I can move to other projects and concentrate.
Another way is to work on a project like the botany one with a definite format. It is like filling in the blanks and takes minimum thought, only looking up facts, rewording them and writing them.
The second reason for staring blankly at the screen is confidence. This usually troubles me when I am tired so getting enough sleep helps. Otherwise my mind is filled with negative thoughts denigrating my writing and me. None of this is real. It feels real only because I allow it substance.
Denying substance to such negativity is difficult. I at times let it fill my head and a piece of paper to toss in the stove letting the negativity go up in flames. Other times I slam a mental door on the thoughts and go back to my Ozarks book relaxing in memories of my beautiful hills until my mind is filled with lovely thoughts.
Then I look at that screen, click on a writing project and write because I am a writer and I can write.