Or else some other shit is distracting you. (I'm a poor multi-tasker, me, if I'm to be honest).
My favourite part(s)?
Definitely, ideas-jamming. That weird metabolic effect where a cup of strong coffee, or a walk, or that 'random' wretchedly-restless, twitchy, inner neural-firing and flexing thing where glucose and actylcholine and synaptic cross-chatter become storified. Where conceptual stuff claws its way to the surface whether you want it to or not. Lays itself out at your feet.
My other favourite thing is where I am now with something else I'm working on: and that's bearing down on a script, hacking / switchbacking my way through panels and scenes, suddenly / unexpectedly switching from scratching my head and rubbing my chin to barely keeping up as stuff starts writing itself and auto-refining / distilling down into "ah, that's it..." details.
When process goes from a canter to a gallop.
I fuckin' love that.