It has been a way I have shown others that I am interested in them romantically and sexually. I view flirting as the fun and life affirming skilled art of flattery. This is not to say that I have limited myself to flirting with only those that I am romantically and sexually interested in. Not by a long shot. Because I also view flirting as a sport and a way to stay in shape verbally, socially and mentally.
Some people play chess or do crossword puzzles.
This is one of the ways I keep my social skills sharp as an extrovert. For example I am not interested in dating monogamous women. Even though I have absolutely no interest in dating them I still, on occasion, flirt with them. I wonder once in a while how they would potentially react to me if they knew I was Poly and had no interest in them romantically or sexually. The potential possessiveness of monogamy is one of the reasons I have no interest in monogamous women.