Good psychology too!
I've noticed a lot of mental health interventions heading towards using mindfulness-based methods, basically training the mind to focus solely on the present situation and not be distracted by extraneous considerations - what's on the shopping list, who pissed you off a month ago, etc. This is not just good for improving mental awareness in those moments, but good practice for being able to pull this skill out when life seems overwhelming and we have to focus on what's right in front of us.
It seems to me few activities, other than motorcycling or meditation, are so good for practicing mindfulness. Zen and the motorcycle riding!
Happy riding for your health.