Obviously jing, our underlying essence which is self-reproducing, is the active ingredient in seman and eggs, creates scabs, and is more or less responsible for our over all constitution--comes to us through our ancestors.
Qi, on the other hand is largely the result of our personal conduct. It is something we choose to cultivate or depleat as the case may be.
The environment is another layer of fateful interaction which tends to be a combination of jing and qi, but could also be thought of as shen. Like external spirits, sometimes it overtakes us without warning. But usually if you're paying attention, and you live in a house, you can see it coming.
Well, last Friday I had a purely conduct induced illness which as I write this is still lingering. First, out of vanity, I got a short hair cut. Second, I went to do some work on my partner's office and I stood outside fixing a sign in a cold wind without much more on my upper body than a t-shirt for almost 30 minutes. Third, I went to the Asian International Film Festival to see a South Korean serial killer film called "Chaser," about a cop who becomes a pimp and then tries to catch a serial killer. (I just looked around for some reviews to link to and didn't like any of them. If you like horror, you'll love it.) Forth, I drank sake in the theater. Fifth, I stayed up way, way, too late.
By Saturday afternoon I was down with a nasty wind invasion in my throat, and a strong sense of regret. Two lines from the Daodejing going off like neon lights in my head:
Why are Daoist adepts not afflicted?
Because they are sick of affliction.