Thomas Edison bragged about only needing a few hours sleep at night, but frequently napped and had cots all over his lab, including one in his office. He judged people harshly for sleeping (and eating) too much and one big motivation for developing the electric light was to make more productive hours available to people.
A lot of writers beat themselves up for sleeping too much – or can’t get enough sleep because they’re anxious about a project, or lack of progress on a project. I personally function best on 8 hours a night and have a hard time napping but different people are different – not weak, stupid and over-indulgent like Edison thought. Although, I admit, he was pretty damn productive.
Read more about Edison’s schedule and productivity on Brain Pickings.
I’m like you. I do best with 8 hours, and it’s damn near impossible for me to sleep during the day, even if I had a bad night.