As a longtime practitioner of yoga and a person who's been involved in physical fitness my whole life, I can tell you, yoga helps you achieve altered states of consciousness. It is not just stretching. The only way you can say that it's stretching is if you haven't done it, or that you haven't done it rigorously for a long period of time.
You're sort of programmed a certain way because of your environment. That's all you know. But we don't have that anymore because of the internet. Because of the internet we're all communicating with each other all across the board, so you're getting information from people all around the world, hitting a much more diverse slice of culture.
No matter how civilized we are and how much society has curbed violent behavior. Human beings still have the same genes they had 10,000 years ago. Our bodies are designed to have a certain amount of physical stress and violence in them. We're designed to run from jaguars and fight to defend our territory.
We're constantly re-evaluating the potential for life. We're finding it where we didn't think it could exist, such as volcanic vents and other extreme conditions like under arctic ice. We're finding life in these incredibly harsh and dynamic conditions, so we're having to re-evaluate our own ideas of what's possible on this planet alone.