Sunday Afternoon Naps

Why is it that a Sunday afternoon nap is so sought after? What is it that makes it so much better than any other nap? If I took an hour or more nap any other day of the week I would be up until all hours of the night not being able to sleep. But somehow, Sunday afternoons are different.
Is it because Sunday is a "day of rest"? And therefore, do our bodies know that a little shut down time would be welcomed? Or am I just tired?
Our home teachers are over and I am listening (or so I thought) and then I get an elbow from Heidi letting me know that I had been snoring. Oops. Hope that they didn't hear.
Guess a little power nap will get me through the rest of the day.