Sometimes we unconsciously reminisce past experiences at unknown times, all-the-while, focusing on the moment at hand. What happened to your friend may have not triggered you laughing at all. --OR-- the action of your friend's predicament, in turn caused you to react with a laugh due to a long-passed, comical memory.
Perhaps it was just the mere coincidence that of your friend's burrito supreme blowing off the table.
Maybe you guys were debating the cheapness of such a product-- that by it being whipped up by the wind, and tossed on the ground, would further support your argument, how cheap it really is.
I'm curious as to your own inferences?
--Rob USMC