For me, reading is about entering an author's world, immersing yourself in their story for a few hours, and leaving with what you need.
For me, nature is a haven of peace and relaxation. Bivouacking gives you the chance to be self-sufficient for several days and to really immerse yourself in nature.
Speedcubing involves solving a Rubik's cube as quickly as possible. It's always a competition against yourself and an intense memory exercise. It's a very complete discipline mentally.
As a nature lover, gardening is the perfect way to bring nature into your home. It also helps to develop patience and attentiveness.