I'd be interested in people's thoughts regarding this question. To what extent does the mood you're in impact the kind of ride you have, if it does, and how does a ride affect your mood, if it does?
If riding is a mood elevator, as I suspect it is, then why? I'd love a good "scientific" explanation. And if it is, then why are there days when I have to sort of talk myself into riding (when I'm grumpy, for example), even though I know from experience that a few miles down the road I'll be glad I got out there? If it's a mood elevator, why would I have to "talk myself into it" at all?
Finally, are there any studies that explore the relationship between cycling and mental health?