My diet is extremely simple. I'm avoiding one thing - wheat. Now, wheat is in an incredible amount of things. Not just breads, pizza, all cakes, all pastries, and pasta - but in gravies, sauces, sometimes French Fries and even frickin' soy sauce. But it's still a simple diet - avoid all of those things.
I do this because I have a wheat "allergy". It's in what Jon Stewart calls "dick quotes" because eating wheat won't land me in the emergency room with an unexpected bill that costs more than a round trip to Paris with a two-week stay in a 5-star hotel. My wheat "allergy" will give me zits.
But if I eat wheat often over a period of time, my skin gradually gets worse and worse until I'm covered with zits. Which is a problem. At the same time, I love breads for the carbohydrate sirens that they are. This leads me to play with fire and eat bread on special occasions, the key word being "occasionally".
Explaining this to my friends and family can be strangely difficult. I find myself constantly having to restate the reasons for my diet for people who've known of this for years. And to be fair, I'm not being consistent. But they've seen the way my skin was, for years before I eliminated wheat. They see how clear my skin is now.
Further, they know cigarettes are bad, and alcohol, and junk food, and reruns of Robocop II for that matter; yet indulges in those directions don't cause them to question whether those items might actually be healthy. But when I break with what's good for me and succumb to sweet, sweet starchness, they seem to wonder whether they're remembering my diet correctly at all.
I think this lack of memory occurs because avoiding wheat doesn't fit with their worldview. Wheat is good and healthy for everyone, according to all forms of mainstream public opinion and American culture. Thus the default network of other ideas that give context to new ones, just doesn't have a place for my contrary information to fit - and so the idea just doesn't stick.
Where I'm going with this, besides just bitching about my friends, is the larger world this illustrates. As humans we don't tend to think about new ideas on their own merits. We see how the new ideas fit in with our current ideas on similar subjects, and accept or reject the new idea accordingly. So to get people used to a particular idea, sometimes you have to either find a good set of accepted ideas that it will adhere to, create a whole new set of ideas that's so enticing they'll take the bunch - or utterly destroy the current network of ideas with a blunt and shocking reality. *
Perhaps somewhere there's a black magic book of marketing which describes this process in far more exacting and diabolical detail. A way to measure the stickiness of concepts, word-shapes and comfortability-matrices. Methods that other warlocks of language use intuitively when they create names for pharmaceutical industry, companies, or the latest Warner Disney Virgin-slut master-jailbait chickiepoo. (It's war out there, people!)
This whole phenomenon of idea adhesion, as observed in my friends and extrapolated to other less strange humans, makes sense from an evolutionary standpoint. It's far more beneficial for us to think in larger patterns and look for wholes, than to deal with individual distinct events or items. It's also how the software of our language-based consciousness works: we create concepts which deal with sets of ideas, because it enables us to organize and assimilate large amounts of information.
It's just freakin' annoying when I'd rather reach for that bagel of a flavor I haven't had in years, and I'd rather not catch an earful. But, maybe that's not a bad thing either. It's not automatically terrible to be consistent.