I'm doing both and love both.
The key is to only work at flying jobs that don't suck, and only buy planes that won't eat you alive financially.
Unfortunately many people can't figure out how to do one or both of those things successfully, hence you'll hear a lot of complaining when the topic comes up.
As for reasons why I do each...I love flying, and fly professionally for numerous reasons. I enjoy the challenge, I'm good at it, the lifestyle is fine for me, and I can't think of anything else I'd rather do to pay the bills. As for why I own a plane, it gives me freedom from the rigors of professional flying, I love taking friends for rides, socializing at pancake breakfasts/air shows, etc. I blow off steam by cruising around low and slow in my 140.
It's kinda like a bus driver who owns a motorcycle. Both are forms of transportation, but reasons and motivations for doing each are totally different.
If I had to give up one or the other, I'd probably give up owning a plane. But only because that's a smaller part of my life than professional flying. I really wouldn't want to give up either one.