i received my Level 1 Reiki certification about a year and a half ago. The initiation was really eye-opening. I have only performed reiki formally on others a few times but I try to tap into that energy often. I am a professional gardener so it is a big part of my work, but even just placing my hand on someone's back or shoulder is enough contact to send them the energy. The experience of bringing another person peace and deep healing is transformative. The few times I have performed reiki on others, they quickly relax (breathing slows, muscle relax, REM beneath the eyelids, even snoring). It is something very primal. There are nerve bundles and energy centers that are stimulated often when we are children but are neglected as adults due to ignorance and social taboos. Reiki focuses a lot on these areas. It is a real feeling of empowerment to know you can affect another's physiology in such a positive way. As someone receiving the energy, I would compare it to the deepest restorative sleep most people have felt. It is like a full nights sleep (or even more) in 30-60 minutes. There is a reason it is being used on operating tables in hospitals now. With that said, it is a two way street. If somebody is not receptive, then I believe them when they say they "didn't notice anything."