1) There are those, probably like yourself, that have a very intuitive understanding of the logic of mathematics. Unfortunately that is not the case for the majority of the population. Students who are taught to memorize formulas show very little ability to apply those to new situations. They cannot see how to manipulate a formula to soplve a problem presented in a new way or in a new situation. Transfer simply is not there. 2) Plugging into formulas to solve problems only goes so far. Eventually we come to a problem for which there is no known formula to solve it. This takes people with an understanding of mathematics, not just people who can use formulas.