I'm sure someone will chime in with 'drugged effect from dying brain cells', but it does sound pleasant.
Well of course! Science has fairly definitively determined that NDE's are simply the symptoms of an oxygen-starved brain. Out of body experience happen all the time. They care called "dreams." Some people have been documented to have 6 or more OOB's per year and it scares the hell out of them every time.
I had one out of body experience as a child that was not due to being sick or hurt. It was my spirit (or something) rolling along with the wind over a field. I could feel the tumbling and see the field go by even though I was standing still holding onto a tree. It lasted for a few minutes. It was a wonderful feeling. I could never duplicate it again.
Yup. And I fly like superman all the time. If I could make myself experience that feeling at will, I would never wake up. It is the most wonderful feeling in the world. But, alas, it's just a dream.
I also have "NDE's" often when I go to sleep. At the junction between sleeping and waking there is a state of consciousness that is wonderfully comfortable. I have taken a nap on a hard, cold concrete floor and still can find that comfortable place. It's difficult to get to. The trick is to keep yourself aware just a little as you go to sleep. There are book devoted to the subject. Some people claim to be very good at it. I only have limited success. Goode "lucid dreaming" sometime.
Nothing magical about it at all. Just plain old extraordinarily complex brain function.