I've found that things that used to seem utterly mundane now seem like special treats. For instance, I never thought anything at all about white rice, but now it's my go-to open meal food, and I have it at one meal at least once a week. That's a low-risk treat, too. I've been much more open to that in lieu of, say, bread or pasta, which I still enjoy, but have grown somewhat fearful of (though I don't usually notice any reaction). Before paleo, I'd never have chosen rice over pasta.
The reverse seems true as well: things that used to seem like indulgences (steak! Hollandaise! Butter!) have found their way into my quotidian diet. I think it kinda cool that my special indulgences are cheap, abundant things like rice, and corn tortillas. And booze, of course.
I don't indulge daily, nor do I typically indulge all day on any given day. I just do it when the mood strikes me. I find scheduled or routine open meals doesn't work for me. It's kinda like sex: I can't plan it, I just have to be in the mood.