To do yoga in your dream, or to see a yogi, is to sink into contemplation and your inner world. It is a signal that you need solitude and tranquility. It’s time you paid more attention to your spirituality and self-development.
To see thorns in a dream indicates that you should spend some time on your own. Perhaps you are tired of all the hustle and bustle. In order to relax, calm down, and reach harmony you can meditate, listen to relaxing music, read your favorite book, and go spend more time outdoors.