For instance, if you like black and white you could mention in this thread that you like black and white. Black and white are indeed considered opposites.
nature and technology. more specifically forests and railroads. not really opposites at all, but many supporters of each see those who support the other as being so. go figure. humans. no logic at all. real fantasy and real science fiction are much more opposites of each other, even though movie goers, movie makers, and librarians all seem to have a hard time telling them apart.
I like roots reggae and black metal. The first is often focussed on equal rights in society, abrahamic religion (rastafari) and morality while the second likes to focus on individuality, a lack of concern for equality and blasphemy. I like to second this one as well.
Hi Fairlight, did you mean consonance and dissonance. Although assonance and dissonance is interesting. It sounds like a heavy metal meets art rock description.