I've also noticed that I have a sort of natural energy in the morning. I think of it as being similar to how a seed has enough energy in itself to sprout and then get sunlight. It's probably so I can make myself eat and whatnot. I don't really need caffeine to "wake up" as much as I need it to stay awake later in the day, and even if I do have a coffee with breakfast, I'll often get tired before the normal day is over.
Falling asleep after a can of energy drink.
This absolutely happens to my father, who uses coffee as a sleep aid but the science is sketchy.
It is documented but I don't know if it is scientifically valid
https://en.wikipedia.org/wiki/Attention_deficit_hyperactivit...
I can't find it now but I once read that people who report the "paradoxical reaction" to stimulants have a significantly better outcome from stimulant medications, and both those values seem to have higher heritability than ADHD as a whole, possibly even linked to a single gene.