Some personal words, as a humble yoga-āsan instructor myself (not a Yogi, please!)
Since i spend so much time in the west, and as a yoga instructor myself, i have observed how yoga has become a commodity... a battle to show teachers in difficult poses to impress and to attract mainly for commercial purposes. many yoga teachers seek to be admired - or want to become 'fashionable' which is even more amazing in the world of what really yoga means. Let's not forget that asana or yoga-poses is a very, very tiny component in the path of yoga. to admire difficult poses and contortions, one can also go to a circus or to a gymnastics competition.. where one can enjoy this kind of show. in general, the asana part in the world of Yoga, has been very much misunderstood in the west - and every time more, due to the high competition in the yoga market nowadays, with millions of certified teachers.
Even if the only yoga pose one can do is sukhasana (cross-leg sitting) it is still more effective and valuable that 100 poses with no understanding of the real purpose of the path of yoga: raising in consciousness. The traditional asana-teachers in India used to teach their disciples only a single pose during months or even years! and now sometimes teachers are making students do challenging poses in their second class. Yoga is about proceeding in life with excellence - excellence in all we do: inner and outer; and excellence is not a skill - it's an attitude. yoga is not separated from our daily lives. yoga is not a fitness class. maybe that's why it is said that shavasana (corpse pose) is the most difficult asana: because it requires the mastering of both the body and the mind.
Let us also understand that the Yoga-asana (exercise, poses) came much, much later than the Yoga as a lifestyle of excellence... So what everybody is calling Yoga, is not Yoga! it is exercise... to that exercise one must add a high ethical moral life and awareness, in order to be able to say that, "i am living Yoga, or i am a Yogi."
If you are interested in asana, it will be a great addition to your life. Just make sure that when you select a teacher, by all means avoid one that wants to show-off what he/she can do, posting photos regularly in challenging asanas to attract attention and use it as commercial tools. The focus of the teacher must the student, not himself - the students must be inspired on why asana could be good for their lives, and how it can bring them to more relaxation, which is needed to think 'right', to take right decisions, to harmoniously live in the world - and remember that by Yoga we mean the real meaning of it: the search of excellence in all we do; yoga is the lifestyle of excellence. By yogic manner, we mean the best manner. And the best is not compared to somebody else, but the best within ourselves. Success in yoga means awareness : living in the moment is the success.
Yoga means union, or 'to join' - to join the lower with the highest.
IF YOU ARE STILL HOPING THAT YOU CAN GAIN SOMETHING THROUGH YOUR MIND, YOGA IS NOT FOR YOU ~ Osho