I wish I knew where this all came from too. I can say with certainty that it did not start at home. While my mom did indulge some of my strange food obsessions (eating everything separately, dying my food green, etc), she did not limit what we ate based on my limited palate. My mom enjoyed cooking different foods and trying different recipes and made sure that every meal had all four food group represented. And I had to eat it all. I didn't have to eat a huge amount, but I had to eat a serving of it. She would occasionally do some things to help out, such as serving my plate before adding the clams to her lemon clam spaghetti, or making sure that I got the serving of fruit salad that had the least bananas, but she wasn't going to go too far out of her way. And not liking something wasn't an excuse to not eat something. So I can't blame my picky eating on lack of exposure at home.
So maybe I won't figure out where it came from, but my experience last night helped reinforce that this won't be the easiest thing I've ever done. It made me think about what I was undertaking and what I might have to make myself eat and I asked myself whether I really wanted to do that. In the end, the answer was yes. So, game on!