People have talked about what makes a good bourbon, but not much on what makes a bad one.

Is it from being too greedy in the distillation process?
Is it from cutting corners making the mash?
Is it from sticking the barrels somewhere unpleasant?
Is it just lack of age?
Is it just by accident?
Something else?

(P.S.: By bad I mean having a terrible flavor, not being bland. You can make a bland bourbon by just using a high distillation proof and cutting it with a lot of water before and after the barrel.)