I used to avoid taking naps. Not anymore. I now have a short nap every weekend day (or non-work day, who am I kidding?).
I wonder how much this is related to having a kid? Maybe fifteen years ago, I was showing someone a home movie I had made of my daughter at the playground. On the screen, we saw the camera slowly turn towards the ground. The person watching with me laughed and said "You were falling asleep!" Without a doubt.
I wonder why I don't nap during the workday, especially since I'm working from home. Maybe my brain is engaged, powering through the afternoon doldrums, while making the computer do things. When I traveled for work, I remember sometimes taking a walk outside and I seeing some people fast asleep in their cars after lunch.
I try not to take too long a nap. 30-40 minutes is my usual duration. I lie down in bed, and read my book, letting my natural tiredness dictate when naptime starts ("reading with my eyes closed"). When I get up (thanks to an alarm), I sometimes wonder how long have I been asleep. 30 minutes seems too short for the grogginess that I feel, or the long, complicated dream I had.
I know some countries have instituted the afternoon nap, called a siesta, as a way to stay cool during the hot weather months. The United States is not one of these countries (though some companies are open to corporate naptime). Productivity at all costs, even if you have to nap in your car! At least I can nap guilt-free on the weekends.