Did you know that the Sanskrit word for "joy" is the same as the word for "space?" I like this.
Shiva, the father of yoga, tells his wife Parvati that yoga is joyfully done. This is a notion I find very compelling and strive to bring into life beyond the yoga mat. It makes sense that giving yourself space, making space for yourself, opening up, makes you more joyful. Suddenly there's room for you to expand, fill the universe with a little more of the pizzazz that makes you 'you'.
This idea makes sense in a pedestrian physical and domestic way too, not just mental. If there is more space in your environment, the more joyful the space is to be in. As an advocate of anti-clutter and no mess, this appeals very much to me. (And as a resident of NYC, we here could all use more elbow on every level).
Downward dogs and mountain poses can help you chisel out space for the mind, for space in your built environments, definitely check out Marie Kondo's charming book "The Life-Changing Magic of Tidying Up." Tellingly, the stuff you should keep around in your space are those she cites as "sparking joy." So, enjoy!