All my breads seem to taste and look the same

I have been working through a few different recipes from the bread bakers bible, and I can't seem to get the breads to differentiate.

I am using the specified ingredients, and following the instructions to a T, and have made multiple loaves, but all of them seem to be on the heavier side, and the results don't really taste that much different from the other loaves, when though one made be made with all purpose, another with whole wheat, and another with bread flour.

I'm wondering if I am making some fundamental mistake, like under/over proofing, over/under kneading, or that one of my ingredients is not working.