When you think about it, it's really amazing how the food industry has taken something as simple to make as popcorn and basically contaminated it by packaging it for the convenience of making it in a microwave. Some added oil, chemical flavorings, and a microwave, and Voila! you have fake butter flavored freshly popped corn. The fake butter flavor is now feared to cause cancer. I can't say I'm surprised. That stuff has no similarity to butter or even margarine for that matter. It doesn't take a genius to realize there is nothing natural about it. I suppose now people will be wishing they hadn't sold their popcorn poppers on that rummage sale so many summers ago.
For those who have forgotten how to pop corn the old fashion way, all you need is heat and corn. If trying it on the stove top, add a little oil along with the unpopped kernals. Keep a cover on the kettle and shake it continuously so the corn doesn't burn. Take it off the heat when the corn stops popping. If you'd prefer to follow a recipe, you're in luck: I found this one for "Plain Popcorn" on epicurious.