I learnt yesterday, watching a British TV programme called 'QI', that most of the moves, positions and general structure of Yoga, as we practise it in the West, can be traced back to only the 1930's.
The positions we incorporate into our Yogic routine (Dog, Salute to the Sun, Crow) are all very recent inventions and adaptations created by those who thought this was a good way to exercise the body and free the mind. And they labelled it Yoga, and gave it an air of ancient mysticism.
Most original Yoga poses are apparently not in any way original 'Yoga' at all, and mostly consisted of... lying or sitting.
We may have been given the impression by our teachers that the yoga being taught was thousands of years old, but in fact, it's barely 100 years old....
Then perusing and doing research of my own, I found this.
Anything else that has similarly disappointed you in some way, through its inauthenticity (Father Christmas, Tooth Fairy!)....?