Personally speaking, both presence and intensity of dreams has almost a direct 1:1 correlation with how much I've learned or participated in mentally challengin

Personally speaking, both presence and intensity of dreams has almost a direct 1:1 correlation with how much I've learned or participated in mentally challenging tasks the day prior. Most of the times I don't remember having dreamt are those when I've been more or less living on autopilot, with nothing novel in work or leisure time. Recently I've had an explosion of vivid dreams that lines up almost perfectly with doing things I'd not had prior experience with when programming in both work and hobby projects. I've been on a pretty consistent one cup of coffee and occasional second cup over the course of the pandemic. The only way caffeine impacts my sleep is if I have it past 1-2PM, in which case I find it harder to fall asleep and may wake up periodically but will still dream.