I think I know the reason. It's because when you get older you lose the ability to hold in your farts. So far, my supervisor has farted in front of me about 2 or 3 times.
One time he came in my office to tell me something and then he farted as he sat down. I kept thinking to myself, if I knew my body was holding in a fart, the last thing I'd do is to go to someone's office to talk. I would wait until I could release it in my office, then I'd go to the other office. What's up with that?