B.K.S. Iyengar said something akin to the following. When an undesirable thought enters your mind, instead focus on your work and see what wins. This is a tool I use every day to manage my state of mind. I find it extremely helpful. If I’m feeling anxious, I focus my thoughts instead on my work at the time and I often find that my anxiety goes away. Work can be anything. It can be actual work, relaxing, sleeping, meditating, eating…anything.