Tropes: Grumpy / Sunshine
Opposites attract. While the previous sentence may not be true for all human beings, the phenomenon happened often enough for the saying to become a cliche. It still pops up in romantic comedies from time to time, usually in the form of a loving jibe or tell-tell remark from a quirky or mysterious supporting character. These days, it is more often implied than said aloud. Many different pairings illustrate this trope, but the most common and beloved is a couple we have come to define as grumpy/sunshine.