When I meet people who seem stressed out (stress/anxiety/worrying), I try to encourage them to practice mindfulness meditation or yoga. I find both of those practices to be a wonderful way to quiet the thoughts in the mind. (It may help to know that the basic practices are 100% non-religious.)
Personally, I enjoy living in the present moment, without thoughts about the past or future. I used to be an angry young man, and using these practices to calm my mind has made my life happier and more productive. A couple of times a year I still lose it, but these practices always help to re-quiet my mind.
(I think the image shown was created by Gemma Correll.)