To be honest, flying a jet is kinda fun, but it is mainly a very tightly regulated job. For real fun, completely on my own terms, i rather fly a puddlejumper, glider plane, hang glider or turn myself into a small plane on my own by jumping out of healthy plane.
It's called recreation and in our profession it has the huge added bonus that it also helps us maintaining a part of our professional skill. I started flying at 14 not to get into a profession, but to have a huge load of fun. Eventually i did turn to flying professionally, but i would not give up flying for fun on my own, only constraints are time and money, and both are indeed crippling, especially with the added financial burden of EASA regulation.