Yeah, boredom is a key, one I remember unlocking creativity when I was younger, and one I rarely can find anymore without effort (like John Cleese of Monty Python sitting in a barren room for four hours, 3.5 hours of boredom followed by a half-hour of inspired writingj[0][1].
I wish someone made the opposite lecture to John Cleese on creativity; I'm stuck in open mode, an endless supply of ideas, struggling to turn off the faucet and actually make something.
[0] Create a space to play (2min clip): https://www.youtube.com/watch?v=GWEXQ9E4QiI
[1] Make time for boredom (36min, Swedish subtitles?): https://vimeo.com/176474304