In adulthood I just don't seem to feel jealousy, I'm curious about why others do.

For instance a few years ago I didn't get a job that I really wanted and had a lot of experience in, the job went to someone much higher qualified than me, although less experienced, who was also 20 years younger. I felt sad, I felt rebuffed, disappointed, but for some reason I didn't feel jealous - she got it because she was the candidate, the employer wanted, good luck to her.

Life is hard enough with hitting oneself over the head with jealousy IMO.