Sound is of course a question of taste, but it has also some basic rules.
Mixing excellent individual instrument sounds will probably give bad results, just like mixing several fruit-juices will probably give just a thick, sweet drink without any precise taste: the individual qualities of each fruit-juice will be lost in the mix.
Take a lettuce, oil, vinegar, salt and pepper. None of them tastes really good one by one: would you drink a glass of vinegar, or eat salt with a spoon?
Mix them carefully, and keep the balance between each of their characteristics: you will have a tasty salad, and will enjoy eating it.
Fruit-juices are very similar in terms of taste: they are all sweet. Mixing them will just kill their individual qualities, cause the individual tastes "overlap".
Lettuce, salt, pepper, oil and vinegar are all different.
Their tastes will not overlap, and if their individual qualities are not obvious, mixing them will give something complete and balanced: acid and sweet, soft and fresh.