Baking is applicable chemistry and tasty chemistry at that. Every ingredient and every environmental condition will have some effect on the finished product. Too much of one ingredient or not enough of another, air that is too dry or too damp, and even the season ingredients were harvested in; all of these are variables in the chemical equation of whatever you are baking. Even a person's mood can really affect the finished product.
Recipes have done most of the equation for you. Follow these steps, use this ingredient rather than that one and 98% of the time you will wind up with a dessert or bread that you can be proud of.
Commercial mixes have simplified the process even further for a person who, doesn't think that there is ever time enough to make something from scratch or doesn't keep some of the basic ingredients on hand. Often, with mixes, all one has to do is add some water then heat for an appropriate length of time and presto! Pull it out of the oven and you have something that isn't quite homemade but it's close enough for most people and is usually is pretty tasty.
However, mixes often come with a hidden price that most people don't stop to consider. They lose sight of the fact that you only needs a few basic ingredients really to make something truly satisfying whether it's a cake, bread, pie, or cookie. They ignore that there are additional chemicals in many mixes that have no use when you bake from scratch: emulsifiers, tenderizers, preservatives, added "fiber", other chemicals to tweak the flavors, etc. I am not advocating that people go and mine their own baking soda, but rather that they stop and think a little bit first about what that "convenience" really entails.
People become insulated from what scratch baking is about, that it's something that can be fun and satisfying to the soul. Trying out new ingredients, learning what those ingredients will bring to or take away from a recipe, adding things at different times , or even preparing an ingredient differently (i.e., butter that is softened instead of melted) can completely transform a finished product.
It's also a way to connect with other cultures, history, to one's present, the future, and one's past, and it's a darn tasty way to do it.
This is the very soul of Chemistry-something I think a lot of Chemistry classes should embrace and take to heart. Now, go bake!