Ok. Because I use to meditate a lot on what I post here ... I often exceed the 30 minutes time limit allowing to edit my post. So, I will just post again, the newer version.
See, how it developed, form the first to the second. Count how many devils are in each of them.
Here it comes again:
Yoga cannot be aquired, yet it can be recieved.
Between an accomplished yogi and the average man of today (I hate to use the term, as everyone posess the greatest opportunities, and is indeed Christ/Atman/Self/Consciousness), the difference is like that between an adult and a child. In today's egositic, individualist world, where criticism and short sighted egalitarianism is so common, it is hard to accept that indeed some might be much more wise and knowledgable than us. To asess a teacher, it already requires certain soul qualities, like openness, tolerance, and the ability to admire and respect. Without the latter, only dry intellectual knowledge is possible, and that is strictly linked to the sensorial world and thoughts about it. It is no wonder that it exist a superficial view of yoga. Why would the yoga phenomenon be free of the everpresent and all encompassing materialism of our scientific culture ?
Yet, for those who desire to dig deeper, it must be said: yoga is not about asana, not remotely (depends on what we call asana). It is just as gross a mistake like saying that the human being is only a physical organism, with it's complex bio-chemical interactions. From this comparison you might draw the following conclusion: the more true for someone it seems this materialist representation of the human being, the more far is one of having a clue about what yoga really is. Yoga is initiation to have personal and first hand knowledge of the basic questions regarding human condition. Not learning a philosophy or accepting some dogma. It is worthless to talk about the Self. Knowing it, realizing it, that is where yoga takes one.
Yes, knowledge of former lives, mastering space, time, mind, and soul; becoming a seer (clairvoyant), becoming a siddha, transcending siddhis, all belong to the path of yoga. But one needs not seek a master by these. The better the master, the more he/she will not make a case of them. Follow yama and niyama, and seek those who seem better at it than you are. This way you cannot go wrong. Seek people who seem to live up to the commandments, or the eight fold path of Lord Buddha, or to the teaching of Jesus. Seeking these will lead you to real teachers, not those who just parrot things their brains have learnt, but those who will be able to take you one step further.
PS. Women are better at teaching popular yoga, as they are more cosmic by nature. But we need not mistake what is an innate, mostly unconscious ability to real knowledge or initiation. I say this with all my love for the Eternal Femninine, and Her many instances present here.