FOR ME, it has to have fewer than 5 ingredients, and I have to be able to read them with ease, to start with. Like, Triscuits are whole wheat, salt, and oil. Easy, great!
Mostly, though, I'm having a "can I make it myself?" question before I buy something. I'm quite capable of making my own breads, crackers, and could make pasta if I had the right attachments for my mixer. I can make tofu, butters, whip, soy milk... simple donuts, muffins, sandwiches, chips.
I can not make goldfish crackers, honey nut cheerios, anything pressed into a particular shape, or anything with preservatives.
I personally choose to buy what I COULD make but don't have time to make. If I am incapable of making it myself, I don't buy it. Because if I can't make it myself, I probably don't NEED it.
Grains can be super processed, or virtually UNprocessed. It all depends on the state you purchase it in. For example, Oats! Steel cut oat groats are less processed than Steel cut oats. Those are better than Rolled oats, which are better than quick cook rolled oats, which are better than the pre-packaged packets. I get the steel cut oat groats, myself, and LOVE the taste and texture. I can not STAND the quicker cooking stuff anymore, though I'll admit I buy the rolled flakes to make granola with.