This! is the reason artists accept serious underpayment, that inventors keep tinkering in their basements, or guys who work in commercial laundries go home to their own laundry rooms to type novels...
The joy! when things fall into place, the plot thickens, the painting coalesces, the inspired metaphor falls from... the air?... the muse?... from who-knows-where? onto blank paper.
Progress on my project. (I'll tell you what it is later - don't want to jinx it.) Meanwhile: Callooh! Callay!
(The guy in the commercial laundry? Stephen King in the early days. Read his On Writing. "Frabjous"? Read Through the Looking Glass, and What Alice Found There.)