It does work for baking, but you have to know, what the ingredients actually do in there. You can substitute flours pretty much as you like, but then you have to adjust the liquid content, to match how much the flours used need in comparison. And same with, if you use different fats, or the type of sugar, or something else added in there, etc. So unlike cooking, and just eyeballing whatever in the pot, you need knowledge before you can start playing around with baking, and succeed. But it is very much possible to do.

This is my mother. Then she's mad/disappointed the cake and cookies didn't turn out well and more often than not they end up in the garbage. I do not understand her.

I basically do that when baking bread, but I also know that the result isn't going to be ideal. Basically I'm trying to experiment to get a good multigrain bread that's packed with extra fiber, but at the same time doesn't use hard to get or very expensive items. Each time I get closer to perfecting the recipe, and learn something new about baking in general. Worst case, I eat the parts that still turn out OK, and feed the rest to the birds.

Recipe IS suggestion. If you look at 10 recipe, all have some slight variations of ratio. You can get cookies that required 2 eggs while some suggest 1 egg and a yolk, some 1 egg, some required oil, others only need soft butter, while some suggest melted butter. A slight variation of ingredient won't really kill the baked goods, it's usually the process of making it and the temp we baked on, because we all use different machine and different supplier of ingredients to make our stuff. You need to understand why stuff works, that's the most important part of baking.

If one does not look at the recipe and then throw it out the window and not measure stuff, it usually won't goes horribly wrong.