How much I enjoy a movie is highly influenced by my expectations of it. Hearing so many reviews about "Joker" being underwhelming, I was pleasantly surprised by how much I enjoyed it. "Avengers: Endgame", a more highly-rated movie, had so much hype and positive press that when I finally saw it in theaters, it was just okay.
Expectations are important in relationships, too. Having a good understanding of what you're expected to do at work, and then meeting (or exceeding) those expectations is usually tied to good performance.
I believe the digital experiences we design work exactly the same way. When you use a device or open an app for the first time, you arrive at the event with a host of expectations about what you're about to experience. Some of that is based on past experiences, and some of that on marketing and advertising you've encountered. Either way, your experience isn't universal: it's characterized by what you expect to see.
So in designing experiences, it's important to consider all of the expectations a user might have about our creation before they experience it. Some of these expectations are likely beyond our control. But being thoughtful about the expectations under our control, just as with relationships or movies, seems like a recipe for success.