I still don't understand how Notch codes so fast.
He quit his day job.
I can get a hell of a lot done in a day when I can actually think of something to do, plus if you have an efficient development environment (keep water on hand/toilet isn't upstairs from you/snacks within reach/cheeto towel

) you will get stuff done much faster.
Disturbances from family also do not help, that's why I have two deadbolts on my bedroom door (yes, two)