Long Thorns, Goatheads, and Vibram FFs

I had planned on a long run in running shoes and a short run in Vibram Five Fingers. Instead I took a long nap with Elliott and did a medium length run in the VFF. If the coffee wasn't enough to wake me up I discovered that thorns from goatheads can penetrate the soles of the VFF. It wasn't enough to stick into my foot but enough so that I knew it was there. If this had been a true barefoot run I would have been quite distressed because when I sat to pull it out I discovered eight of them in the sole of one shoe. I continued to run on trails in fields but when I came to a big square field that only had a trail that crossed it I ran the edges to get more distance. Unfortunately bushes with very long spikey thorns grow along hedgerows and break off and are camoflauged where there aren't trails. I stepped on a branch I didn't see and one of these thorns went right through the rubber and rather deep into the ball of my foot. (No significance that this happened on Easter, I hope) I sat down and had to pull rather firmly to remove it. It hurt for a a few minutes; I'm just glad my tetanus shot is up to date.

The outing was 5.5 miles. Barefoot seems so the right way to run. My calves are sore, which I take as a good thing. I took Elliott for a walk in the running stroller today wearing the VFFs as well and it occurred to me that it is even a bit jarring to walk with a heel strike without shoes. How much have shoes changed how we walk even?