How can one fast food joint, in the same chain, that use exactly the same supplies from the same source, to make their food, be good, and the next be bad? The Sonic in Sand Springs has terrible food, and the Sonic in Sapulpa, 5 miles away, is good, and serve the exact same menu?
The same way that people use the same grocery stores --- there are people that can make anything great and those that can screw up opening a can.
.