If you're already a fan of adult coloring books, then you don't need me to tell you how relaxing it is to lose yourself in the mindful meditation of planning out your color palette, choosing your medium, whether crayons, gel pens, markers, or even a combination, choosing colors and filling lines.
If, on the other hand, you're new to this hobby - beware Coloring is addictive. It calms, it soothes, it offers a harmless and helpful escape from stress and anxiety. It is also highly pleasing as completing a design not only fills you with a sense of accomplishment, but it leaves you with a piece of personally-created art.