Most of those I know who fly professionally who don't like to fly for fun or to fly when on time off are those who fly for an airline.
Personally, I fly whenever I get a chance, professionally or otherwise. To this day, I still feel fortunate every time I get to go fly, regardless of whether it's an employer telling me where to fly and how to fly there, or me sneaking a trip around the traffic pattern.
Flying for a living, however, does become a job; it's not a lark. I used to get comments from airline pilots about my firefighting; they'd say it looked like something fun they could do after they retired, as if it were a hobby. No; it's a profession. It's a lifestyle, too, but it's a very serious, no-foolin' professional occupation, and doing that job should be approached accordingly.
Doesn't mean one can't enjoy it, though.
It's perfectly acceptable to enjoy an emergency, as long as one didn't create it.
The State of California CDF aviation fire program adopted a statement I made years ago, on their posters; "It's not an emergency. It's our job."
We did fourteen loads on a very explosive fire a few days ago, which threatened structures, exhibited extreme fire behavior, and was spotting downrange and making it's own weather. Some of the drops were technically demanding, and a couple of the runs into the fire were breathtaking, literally. Last flight of the day, very close to dark, I had just punched off the load when the air attack called to ask if I had any left; a hotshot crew was in trouble and calling for a drop. Nothing I could do. Return and hold, he said. I finished the day exhausted, but without regrets. Do what you can, do your best, and do it again the next day. As long as you're able to do it again the next day and you can do it with a clear conscience and to the best of your ability, and your ability is good enough, then one ought to be able to remain in the job as long as one can look forward to that next day as much as the last.