Personally I think its your fault, you initiated the situation and pushed the guy.
Anyway, similar story, i almost got into a fight at the gas station cause the guy was beinga dick. I had finished filling my car and he was right up against me. but the person in front of me had an longer then average car and made it so I couldnt really move forward to pull out. sO I signaled the guy behind me to move back, he refused and told me to go and started honking, so I got out and told him to move back and he said for me to make him, casually moving his hand to show he had a knife in the car, to which I pulled out my knife (which was so much bigger then his) and said thats not a smart idea, cause youre still stuck in that car.
... but the situation resolved itself when the person inf ront of me finished filling nad left, so I got in my car and left Though I'll admit, its probably more my fault then his.