Black coffee made from instant coffee is understandably horrifying and tastes like ammonia smells, but have you considered fresh coffee? I don't mean filter coffee, either, the filter paper absorbs all of the tasty coffee oils, leaving only an ashy aftertaste, I'm talking espresso, moka pot, greek / turkish coffee and french press.
Similarly, if you normally find that you hate dark chocolate, perhaps it is because your chocolate is made with slave labour and also not very good.
I am currently enjoying a fine ten year old aged Java. It is very tasty, and I highly recommend.
I keep hearing about this mythical wonderful tasting coffee, but I've had coffee from multiple places, had Arabica and Americano, had different African varieties, had it from maybe around 10 different places, made my own by sticking full beans in a cup and pouring hot water on it (cause I have nothing to crush them, and besides, I heard (brewing?) full beans is actually not bad), had both normal coffee, decaf and swiss water technique decaf (higher decaf percentage), and they all taste like mud.
Currently I add about 15 stevia tablets to my black coffee, and that makes it drinkable; if I'm feeling particularly exotic, foreign and a touch mysterious, I'll add skimmed milk.
I feel like origin has less of an impact on flavor than freshness and roast level. Arabica is a variety of coffee grown everywhere and Robusta is the other common variety. Arabica is known for its better flavor and robusta is known for its harsher flavor and higher caffeine content (maybe?).
Brew method is the other important variable and I find immersion styles like French Press to be rather foolproof as opposed to pour overs and drip. Grind size just means available surface area for extraction but that can be altered with time, temperature and pressure.
I like using turbinado sugar and bit of evaporated milk or cashew milk.