Così fan tutte
From The Metropolitan Opera website:
The third and final collaboration between Mozart and librettist Lorenzo Da Ponte is a fascinating paradox: a frothy comedy of manners with an intensely dark take on human nature; an old story (it has antecedents in Boccaccio, Shakespeare, and Cervantes, among others) with a startlingly modern tone; and a beautiful score depicting questionable behavior. Così fan tutte was only moderately successful at its premiere and remained just outside the standard repertoire for more than a century. Così still poses unique challenges, and correspondingly unique rewards, for the public today. Every possible impression of love—from the loftiest to the basest—is explored in this extraordinary opera.