My roommate brought the following home for me from Trader Joe's, unsuspecting the mockery to follow:
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Vegetarian shaving cream? Really?
Which of course created the following chain of thought:
Since you don't eat shaving cream why bother...
followed (naturally for someone like myself) to the exclaimation... "My god, its Soylent Green Shaving Cream" because if its not 100% vegetarian for eating then it must be made of 100% vegetarian(s).......
Then it only took me a few minutes to explain my reasoning and the required pop-culture references to my roommate to explain why I was so amused...