The physical practice of yoga is built around Yoga Sutra II 46 Sthira Sukham Asanam, which means that the posture should be a balance between effort and relaxation or strength and softness. For many of us yogis, it may be more difficult to get relaxed and soft. But without these important qualities, you can't find that kind of balance in your practice and life. If you are too rigid, it is lack of stability. If you are too weak, it is also unstable. Being gentle and accepting may be a challenge, but the benefits are manifold.
In yoga, we seek a samadhi feeling, a mental state in which your attention is clear, concentrated, firm and relaxed. One of the lessons of yoga trip is to discover the difference between being and doing. In active Yang exercises like Astana and Wenyasa, it is easy to focus on the movements and strength needed to complete the shape of Verahard Lassana (warrior) 1 or Natarajasana (dancer's posture). We are used to working hard, aren't we? But if you push too hard, you will fall down or you may hurt yourself. To truly reach the Sthira Sukham Asanam in a pose, it is a dance to relax your body and spirit, just as it tries to land with your feet and stretch your arms to the sky.
Slow down and allow yourself to accept and enjoy slower exercises, which will eventually make you stronger when doing anything. In yin and restorative yoga, passive and simple breathing is totally acceptable and necessary. This is an opportunity to soothe your nervous system and restore your endocrine and digestive system. Simply lying on your back on the sofa can get a lot of benefits, so why is it so difficult to relax yourself?
We've all heard that the strongest tree bends, so it won't break. So do we. We want to be soft, not fragile. The time spent in more "lazy" yoga will eventually help you become the most balanced self, not only in your yoga practice, but in your life.