I’ve mentioned before that I’ve had great success with the book Learned Optimism by Martin Seligman, a pioneer in research on happiness. Of course nobody says that you have to be happy all the time, if that doesn’t work for you. But the OP asked how to maintain a good mood, and there are definitely techniques that can work.
I disagree with the idea that everyone has a basic mood that they’re born with, or at least that this is unchangeable. There are too many simple techniques that can be used to change the way you see life, and consequently how you feel. There are some people who are just happy, and don’t need to use gratitude logs or any other specific approach to make them feel that way. But that doesn’t mean that no one can benefit from working on their mood. Just because some people can sit down at a piano and play anything by ear doesn’t mean that others wouldn’t benefit from lessons and practice.
If you don’t want to change your mood, that’s fine. But optimism is a skill, and if you want to achieve it, there are things you can do to make it happen.
I’m in a good mood for the most part. Maybe it’s because of something I do, but if so I’m not really aware of it for the most part.
First of all, though I have some troubles like everyone, in my opinion my life kicks ass. Not only my life - life in general is just wonderful to me. There are so many interesting things, cool people, and amazing experiences. Plus the awesomeness of just doing nothing, one of life’s most delicious luxuries. But to be frank at times when I was broke, in bad relationships or unsure of what I should do with my life, I wasn’t actually noticably unhappier in terms of mood.
Second of all, most things are just bullshit anyway, so, in the words of my grandfather who survived Auschwitz, “why make miserable?” I notice when I do get wound up about something, it’s terribly exhausting. I’m too lazy to be in a bad mood. It seems like so much work.
I realize it isn’t for some people, it’s more like the default, I’m just trying to answer the question as a person who is rarely in a poor mood. And usually when I am, it’s because I’m hungry and my mood springs back as soon as I’ve eaten properly. However all that said, I have been depressed once in my life, I can remember it, and I am sad for people who are experiencing that frequently or all the time.
There’s a quote attributed to Abe Lincoln to the effect that most people are as happy as they’ve made up their minds to be. Americans who get elected president tend to be upbeat, confident individuals. That level of personal agency, to have the power to determine their happiness, is a lovely ideal to aspire to. But you know oftentimes real life just does not cooperate with how we’ve made up our minds it ought to be. If we had that much power, I suppose we’d be Übermenschen. You can have a lofty ideal to aspire to, to be inspired by and live a good life in its light, even if you never attain a complete level of idealistic perfection. I personally believe that goodness of character brings happiness, and consciously work on myself to realize it.