Count me in, I can't nap either.
I wake up anxious and my heart is racing, and I have hard time to really wake up, keep falling asleep.
I feel like napping only when I have bad anxiety, so my guess will be, it is the initial anxiety that makes me want to nap, as normally, I don't feel need to nap, if this makes sense.
So, when I feel like napping, I know, I wake up with bad panic attack and racing heart...and this weird feeling of paralysis and loss of reality.
I wonder if kids feel the same way, when they wake up cranky and crying. Interesting, that I always have bad dreams when I nap, it can be all connected in my crazy brain.