Oh yeah, MB turns you into Lord of the Flies. I cart check and elbow people out of my way when I'm there, which I would never think to do in another other environment.
I also think the Somerville MB is a whole different animal. I went to the Woburn MB a few weeks ago, on a Saturday no less, and was shocked at how civilized it was in comparison.
The parking lot at the Woburn MB is horrific. I have never been to the Somerville location and don't plan to. I will say, I am MB loyal. I cringe at the prices at Stop&Shop in comparison.