The perils of local experts

I occasionally get in to arguments with people about domestic things -- not domestic politics, domestic things, like "what's got more caffeine, tea or coffee?" or "what do they do to make chicken?" and someone will inevitably say, apropos of caffeine for example, "well, I work in a Starbucks/Tim Hortons/Whatnot and therefore I am the authoritative source on...."

One big problem with his tactic is that I have too worked in various positions where, theoretically, I "should" know something. And more often then not, I've given some half-assed answer to a customer because I'm too pressed for time to think hard about the topic. So I simply don't trust most people who work in their avowed jobs to know what the hell they're talking about -- and I apply that standard to myself somehow...

Anyway, this is all pertaining to this from Julia Olmstead at Gristmill:

The conversation went something like this:

Me: Hi, do you have any grass-fed beef?
Butcher: Hmm, grass-fed? I don't think you can feed grass to cows.
Me: Well, they're ruminant animals, so I think that's what they're supposed to eat.
Butcher: [sympathetic-but-authoritative head shake] I don't think so. They need vitamins and minerals and stuff.
Me: Uh ...
Butcher: Now this [points down at large, marbled slab in meat case], this is corn-fed beef.
Me: Yeah, well, um, thanks anyway.

That's right everyone, we can all put away those textbooks which say cows have multiple stomachs for digesting grass cellulose because -- the butcher said! -- cows eat corn.