This transformation is so fundamental that it's near impossible to convey to those who haven't yet experienced it. I vividly remember the afternoon when it swept over me as I read Will Tuttle's The World Peace Diet. I knew that my worldview and way of life would never be the same. It's the uncanniness of the paradigm shift that has led some vegans to say, "don't tell me that you understand why I'm vegan, because if you truly understood, you'd be vegan too."
Vegans often speak of feeling inner peace. Some attribute this to no longer consuming the products of fear, suffering and violence, to no longer taking in those violent "vibrations," while others attribute it to the fact that their minds are finally free from the constraints imposed by blocks to their intuitive awareness and compassion and the daily rationalizations required to sustain these blocks. Most of us don't realize just how uncomfortable we are with using animals until we stop.
For this reason and others, going vegan is often accompanied by a surprising sense of liberation and relief that we are no longer directly contributing to the unnecessary suffering and death of our fellow earthlings. When we feel the deep gratitude that comes with the fact that no one had to die for us to live, we tend to want to return the favour. It's as though once the cycle of taking beyond our needs, taking the life of someone who wants to live, comes to an end, and that our orientation toward the world fundamentally shifts. This orientation becomes one of gratitude and generosity.