Type 1: In a typical quickbread (and certain cake recipes), the instructions will say to mix just until combined, no actual stirring or beating. I think this is because (assuming this is made with wheat flour, either white or whole), overstirring or beating would cause the gluten to develop which would result in a chewy texture, not usually desirable in this case.
Type 2: Then there's the type of cake where the sugar and butter are creamed and then if I recall eggs are added and then the flour. It's not a problem to continue mixing it, in fact mixing is not only okay but required. This tends to result in a light, fluffy cake.
My question: If my premise for Type 1 is correct (overbeating develops the gluten), why does it not hold true for Type 2?