Notice how you feel when in a good mood. You’re alive with energy, food tastes great, people are enjoyable to be around. Life is good.
In a bad mood, you feel drained. Food doesn’t taste right and people get on your nerves. Life seems bleak.
Barring chemical imbalances, moods are habitual. They don’t just happen, you choose them. Maybe not consciously but you did make the rules.
Here’s how it works. In the past, you reacted to a situation and that put you in a mood, good or bad. Now you have an association of a particular mood with certain conditions. When similar conditions occur, you duplicate that mood.
You don’t have to be in a bad mood just because that’s how you typically react. It takes a conscious decision and practice. You can be in a good mood even when things don’t go your way. Answers and solutions then appear where before they couldn’t.
The natural human state is to be happy. Not necessarily jubilant and bubbly but pleasantly comfortable within yourself. Develop that and improve your level of enjoyment.