I once, somewhat jokingly, presented a formula that went something like this:
Yarn (and knitting) makes me happy. And (to borrow from "Legally Blonde") happy people don't kill people. So really the ruse and stupid people I encounter are being saved because I sniffed a little wool (or cashmere, or cotton, or silk, or bamboo...).
And the Yarn Harlot recently(ish) asked a very good question:
How do non-knitters handle stress? I mean, I know they must do something, since it's not like I see them all weeping on the bus all the time, but when everything in their lives is all messed up, what is the thread of sanity and sameness that runs through it and keeps them from being a lunatic? Does knitting attract people who need something to moderate stress more than others? Do you think that you use knitting to moderate your behaviour, and in this spirit of this shirt (I knit so I don't kill people) do you think your behaviour would be different if you didn't?
Now I have made it to this point in my life without killing people (as far as I know) and I was not knitting the whole time, but I absolutely turn to knitting when I am stressed. I keep a project by my work computer both to while away the time while a large document is opening or to keep me from surfing the web during conference calls but also for those moments when people are ticking me off. So, it's also helping keep me employed.
I don't know if knitter are stressed or stressed people are knitters any more than I know if impatient people are knitters or knitters are impatient, but it does make me wonder about the non-knitters. Perhaps they should teach people to knit in prison.