Meditation when I remember to do it, but the real game changer for me has been floatation therapy. And combining the two by doing guided meditation while I float is amazing and leaves me feeling a high that lasts for hours afterward.

For those wondering what floatation therapy is, you enter a large tub of super salty water and lay down. Because of all the salt, you will float instead of sink to the bottom. The one I go to lets you control the lighting and allows you to listen to different sounds or music, or some guided meditation. I usually turn the lights off, float, and let the guided meditation relax my body and my mind.