I've had a strange combination of conversations across different parts of life recently about what happiness is, and my resolution that happiness is a choice is surprisingly controversial to some, and even perceived as outright wrong by others. Let me explain myself a bit.
People encounter bad and negative things. There is no doubt that people can not control a great many things, whether it be depression, a death in the family, divorce, financial hardship... there's no limit to the list. You can't simply choose to not feel negative emotions over these kinds of things, and I'm not suggesting that you can, or that you should. We as human beings need to process yucky things.
There are also a lot of things that we simply don't want to do that add up, in all aspects of our lives, including work, home life and everything in between. They include things like grocery shopping, paying bills, commuting and writing TPS reports. There's a whole category of things that just come with being an adult that we would probably not do if we could get away with it.
So there is no universe where we can be happy at all times by way of external factors. Like everyone else, I'm going to encounter my share of shit and have to do stuff I would rather not do. But life in aggregate is of course a journey, and it is one that ends in death for every single one of us. This reality forces us to make some decisions about how we choose to view life, while it lasts.
I don't know if my strategy will work for everyone, and I would preface this by saying that it is not infallible, and like everyone, some days will be harder than others. While it's hard to choose a feeling, it is possible to choose to think about the things that contribute to making happy feelings. I try to shift from thoughts of my parental struggles to the love that my child can exhibit toward me. At work I try not to linger in struggle when I can celebrate wins and progress. In all cases, I don't rely on external factors to make my happiness. It's not up to my family or my job to make me happy.
There are certainly situations that you have to change when external factors weigh too heavily on your life. Steve Jobs was famous for saying, "If today were the last day of my life, would I want to do what I am about to do today? And whenever the answer has been 'no' for too many days in a row, I know I need to change something." I've made changes to relationships, jobs and other scenarios in those cases, and eventually come out in better shape.
None of us are entitled to happiness. Heck, even the Declaration of Independence refers to the pursuit of happiness as a right, not the happiness itself. (Mind you, the founding fathers didn't think it applied to everyone, but that's a topic for another day.) There's something freeing about accepting the accountability of your own happiness. You must focus on the things that you can control, and yes, they may be hard to change. Life can be hard, but it doesn't mean it has to be unhappy.