It felt like this 2002 comedy came out of nowhere and really took everyone by surprise. My Big Fat Greek Wedding wasn't exactly projected to do so well, but it ended up becoming the highest grossing romantic comedy of all time (until another movie took the record in 2016). We had no idea how successful it was at the box office - but we absolutely loved the movie, so we're not sure why we're so shocked.
The plot involves two people who are about to get married. The catch is that the bride is a Greek American, and with a Greek family there is nothing short of complete chaos when a wedding is being planned. It wasn't just a hit at the box office, it was also nominated for an Academy Award for Best Original Screenplay.