Comparing yourself to others makes you doubt yourself, feel jealous and all other kinds of negative feelings.
Perfectionists only see what’s missing. In the process, they fail to see the 96% already there. Focusing on the lack fuels chronic unhappiness.
Someone who believes that life is hard and “out to get them” will always find proof of this. It's called confirmation bias. It's not right or wrong, but it will make you unhappy.
People with chronic unhappiness are often deeply lonely because they expect the worst from others. This doesn't allow for happy relationships.
Gratitude is a practice. Really unhappy people often forget to practice it. If you ask them what they're grateful for, they don't know. But gratitude breeds happiness!