What is an appropriate cocktail to serve in a rocks glass?

Serving whiskey on the rocks in a rocks glass is appropriate because the rocks glass, also known as an old-fashioned glass or lowball, is specifically designed for serving spirits directly over ice. This type of glass enhances the drinking experience by allowing the drinker to enjoy the aroma and flavor of the whiskey while the ice gently chills and dilutes it.

In contrast, cocktails like a martini, mimosa, and piña colada typically require specific glassware that caters to their unique presentation and consumption methods. A martini is usually served in a stemmed cocktail glass to highlight its elegance. A mimosa is often enjoyed in a flute to showcase its effervescence and fruity colors, while a piña colada is more suited for a tall glass or hurricane glass to accommodate its blended texture and garnishes. Thus, whiskey on the rocks aligns perfectly with the characteristics and intended use of the rocks glass.