Happy people have a vast amount of things that they consider to be okay. We all have our limits. But we can develop attitudes and reactions that enable us to accept, tolerate, and ignore many of the things that annoy, irritate, and frustrate unhappy people.
Some people need things to be "just so" for them to feel comfortable and happy. The more rules and specifics that are needed for this, the more likely that a person will experience much unhappiness.
Are there any people you dread interacting with? Those with a low threshold of okay-ness are often in this category. They demand that everything has to be exactly as they wish it to be for them to be satisfied. These people are highly critical of others. They get annoyed at others for minor and trivial matters that are not to their liking. Don't be one of them for your own benefit and the welfare of those who interact with you.
Develop a sense of perspective. Keep asking yourself, "How important is this for me to fulfill my life's mission?" The clearer you are about which values are truly important to you, the easier it will be for you to accept and cope well with trivial and minor aspects of life that are not just the way you would have wanted them to be.
(From Rabbi Pliskin's "Happiness",p.50)