for well freshly (in a week) roasted (Agtron 50 to 60) good coffee (pacamara, bourbon, caturra, marago) does not need any sugar.
however, when it gets too old or over roasted, I need couple of t spoons of sugar.
sometimes, I come across really bad ones, it is called rechazo, rejected beans, from processing. floaters, fermented, broken,...etc, they sell them to local cheap coffee shops (around $2 per pound). they are extremely bad. I got to put as much sugar and cream as possible to kill the coffee taste. (i had one in Panajachel yesterday.) still could not drink more than 20% of the coffee.