I had an instructor during my teacher training, who emphasized the importance of "play" and "pleasure" in a yoga practice - something a lot of practitioners often lose sight. After having us stand in tree pose for a couple of breaths and noticing the seriousness of our expressions as we tried to maintain a balance on one foot, he reminded us that we are in fact adults pretending to be trees. There was an immediate release in the room. It was humbling and brought back a perspective to the practice.
It is easy to get caught up in the movements, the exact alignments, the engagements of your muscles, and the concentration of your breath and balance. However, it is a "practice" in which no perfect form exists. Your flow in and out of postures should be comfortable and in accordance with your own body. Nothing comes of twisting and contorting your body into that ideal pose, where you cannot fully breathe and your only thought is when you can release the posture. Your entire practice should be the release - the release of judgement and expectations - and the joy and pleasure from finding a deeper connection with self.
"The Yoga of Pleasure" by Sally Kempton
Finding Joy in Your Journey