A lot of the time when we get upset or frustrated or disappointed about something it isn't because said thing is bad in and of itself but rather that our expectations of said thing have not been met. We expect someone to treat us with respect and when they don't we get angry. We expect our spouse to have the dishes done when we get home and when they don't we are disappointed. We expect other drivers on the road to not break the rules and not cut us off and when they do we become frustrated.
Instead we should live without expectations and allow things to just be as they are. As the Dalai Lama said, "I am open to the guidance of synchronicity, and do not let expectations hinder my path."
I see this kind of dissatisfaction from expectations a lot when it comes to film adaptations of books. Most of us can relate to the saying "the book was better." This is directly related to us having expectations. When we read, say The Lord of the Rings and then watch the film version, we already have a mental image from reading the book of what Frodo or Elrond or Weathertop should look like. When these fictional characters and places show up onscreen and they don't match what we imagined, we become frustrated and react by saying "the book was better."
However, this doesn't need to be the case. A film adaptation is exactly that: an adaptation. It is the film-maker's interpretation of the literary material. Of course it won't be the same as what you imagine or even what the author imagined. It isn't the same as the book. It couldn't possibly be the same. One is made up of words on a printed page that we have to read one at a time. The other is made up of moving images that we see all at once. The two are constructed by two totally different individuals with their own artistic sense and ideas and experiences. We get the information in a totally different manner from these two mediums. You can't really compare them. It's like saying the recipe of a cupcake is better than the cupcake itself. If the cupcake isn't good, it's because of our own imaginations of what the recipe could've been, not based on what it actually is now.
The same can be said of our expectations in real life. What we have in our minds of what the external world should be like is not the same as what it really is like. Ideas in our mind are not the same as actual events occurring before us. Next time we are frustrated or angry with unmet expectations, perhaps we should take a step back, accept the things that are outside our control, be grateful for the experience we receive, and let it go. Take your expectations and throw them in the ocean.