You just disqualified yourself by saying Starbucks is pretty good. With all respect, it isn't, and not just it isn't, it really, really, really isn't good by any quantifiable means.
Most of their coffee tastes burnt, As beans from the same place will taste slightly different from year to
year (yet alone all the different places they get them from), blending
and roasting very dark helps get rid of those subtle flavors for a
controllable "uniform" flavor, in a way, to ruin the coffee.