Dave doesn't need tryptophan or anything like that to take a good nap. In fact, he doesn't think he needs any reason at all to nap, and he thinks people only really talk about tryptophan around Thanksgiving because they want an excuse to take a nap. Dave looks at things a little differently. He doesn't pretend to need an excuse to nap, and he pities those who think they do. Napping is one of the great joys in life, and Dave knows he owes much of his happiness to his tremendous napping abilities, as well as his plentiful opportunities for naps. That's why he wishes society would be more accepting of naps so that everyone could nap guilt-free. Not everyone can be as immune to peer pressure as Dave is.