What Chris wrote was pretty good. I'll have to add that to my mindset and play with it.. My instructor taught that the committed attack was the knock out blow. That is the one to be most worried about. The jabs hurt, but won't due much damage. It is also not easy to control the committed attack. Trying to connect then blend is not easy while staying, centered, and in balance.
When I was in college, I boxed for a little while at a golden gloves club run by a guy named Bob Beal, former amatuer heavyweight. http://en.wikipedia.org/wiki/Robert_Brutus_Beal
Bob told us that nearly all his wins were by ko, and only a few of the kos were not
from jabs. You honestly could not hold onto the focus mitt for this guy - it would just get ripped right off your hand. So, and not that everyone can deliver one, but a jab may be a knockout blow, for someone who knows how to throw one. Just some grist for the mill.
REading the wiki article, I had no idea Bob knew Fred Degerberg, another guy I trained with very briefly. I believe I still have a "Bushido Fighting Society" t-shirt with the logo from the last photo.