Steve, you are so right; they were having the time of their lives.
Short story: My drummer moved to California. We worked together about four years. On a return visit I booked him on a job. We were playing a disco, Manhattan Skyline. Both the drummer and the organ player started to trade fours, they were reaching a music high, it went on for eight minutes. When the song was over the drummer dropped his sticks; the organ player jumped from his chair, and they stood in the middle of the dance floor hugging. Everyone was out of their chairs applauding.
We had just gone through a magical musical moment. It does not happen often; but it will never be forgotten. The magic of music, how blessed we are.
It is magic, John C.