As it so happens, I got thinking about ONS.
Personally I think that the sex is usually bad-to-average, but not good. I enjoy them most because of the novelty factor - finding out about how a new person looks like and acts in that situation. After quite some of them I have started feeling emotionally drained, though, and nowadays want to connect with the other person emotionally as well as physically. That way, the passion can be much deeper and more fulfilling. Still, each ONS represents a story and is, in a way, an adventure.
What do you think about ONS? Have you had many of them? Do you find them good, bad or just feel indifferent about them?