Unhappier people unconsciously look for problems to extrapolate. And do you know what - they will always find them. Perfection does not exist outside the movies. If you look for problems and focus on what's not right in any given situation, then that is what you will see. And your subjective reality will consequently feel less happy. If you habitually look for problems, you will find them. Period.
A happier person can be in the exact same situation and choose to accentuate what they find there that is positive, and be far happier, even though nothing about the circumstance is different. Two people can stay in the same hotel and one have a wonderful stay and enjoy good times. The other can give a scathing two-star Trip Advisor review for the exact same experience.
As Dickens opened A Tale of Two Cities:
"It was the best of times, it was the worst of times, it was the age of wisdom, it was the age of foolishness, it was the epoch of belief, it was the epoch of incredulity, it was the season of Light, it was the season of Darkness, it was the spring of hope, it was the winter of despair, we had everything before us, we had nothing before us..."
You can, through choice of thought, take life either way. Happiness is subjective. It is determined nowhere near as much as we think it is by the circumstance of our lives being perfect.
It is less about being happy because everything we want is going our way, and much more about being happy because that is the way we want to go.
It is a tale of two mindsets. And the good news is you get to choose. #happypeopledon't