So Why Vegan?

Random Stranger: So, why are you a vegan?
Me: Do you really want to know, or are you just making conversation? Because it's a long answer--you can't leave out humane, health, environmental, world hunger, etc issues.
Random Stranger: Uhhh...

Random Stranger #2: So, why are you a vegan?
Me: Let's start at the beginning. You know how everything is a social construct? That is, rules and customs are set up by certain cultures, so people know how to live by pretending that these ideas actually exist?
RS 2: Sure, I've taken a sociology class. I'll play along.
Me: Think of it this way. You've had a pet--a cat or a dog, right?
RS 2: Sure.
Me: But you know that other cultures eat cats and dogs, right? So what gives? Do they just not know that cats and dogs are pet animals, not food animals?
RS 2: I think I see what you're getting at. The idea of a separation between pets and farm animals is a social construct, and the line varies between cultures. So what does this have to do with being vegan?
Me: You can live your whole life eating pigs with a dog in the house, and maybe even think about how farm animals and companion animals aren't really different, and probably even know that pigs are generally smarter than dogs and abused horrifically in the factory farming system. And a lot of people function with that knowledge every day, and continue omnivorous lifestyles. But if one day you get a paradigm shift, where the significance of it all finally clicks, then you'll stop eating meat.