It is. But not the choice you probably think it is.
"Stuff happens, moods and feelings happen, emotions happen, it's how it is. Sometimes I feel good and sometimes not...right?" Yeah. Kinda.
Feelings don't just happen, you create them.
You feel good when certain things happen and bad when other things happen. You feel good when you're wearing a new shirt. You go out and you're walking on golden wisps of happy sunshine, owning the night. Then your lucky shirt breaks. Why?
The shirt was never lucky. You made it lucky. Really. You decided that it was your lucky shirt. Then it wears off, pardon the pun, when you've worn it a few times or whatever other condition that you've made up for it to not make you feel good anymore is fulfilled.
What made you feel good was the meaning you attached to the shirt. Same thing with everything.
Everything that happens is neutral. Like Switzerland or the colour beige. Neutral. Everything that happens is as it is. Even the most heart-wrenching or magnificently glorious moment is just a situation. You feel things about it because you make it into a story...and you're invariably the star of the story so it seems super important but it's still just a story. Just a situation.
You feel good or bad because you attach meaning to that situation.
What's interesting is that it's all automated, this whole system of giving meaning to situations and feeling a certain way as a result. It's so automated that we don't even notice it happening.
See, you have a certain set of rules or conditions in your mind that when certain things happen, you feel good. And other things that happen make you feel bad.
But then if feeling good is something you're creating when certain things happen, why not just drop the whole condition thing and feel good all the time? Throw a spanner in the automated process of giving meaning to things and stop letting how you feel be controlled by it.
Might be tough at first to allow yourself to feel good all the time but what you can do is to stay neutral and not attach meaning to whatever happens. When something bad happens, it happens. It doesn't mean anything unless you make it mean something.
Stop creating stories about things that happen. Stop giving things meaning. Things happen. It's done. Let it go.
Easier said than done? Maybe. At times, definitely...
When something seemingly bad happens, it's just a situation. Don't call it good or bad. See it for what it is, a situation. Creating stories, creating feelings about it will make you feel worse. Just stay neutral about it.
...so a little practice that I find really helps is allowing yourself to become transparent to whatever happens. Whenever something happens and you feel an emotion come over you, literally imagine and feel yourself becoming transparent, almost as though you dissolve so that the feeling can't get trapped in you. You don't grab whatever happens and turn it into a feeling, it just gently goes through you and dissolves.
That will help break the cycle of continuously giving meaning to things.
You don't even need to choose to give things positive meanings to make yourself feel good ala "seeing the best in everything" because feeling good isn't about creating the feeling. It's about not creating other feelings that cover up your natural state of limitless bliss. Feeling good is your natural state.
You don't need to make yourself feel good. Just stop making yourself feel bad.
When you stop making things important and allowing your feelings to be controlled by what happens, you stop covering the indescribable magnificence of your true nature - essence of feeling good, the source of all good feeling - and you are reconnect to that which you are, instead of thinking that you are your stories. You stop making yourself feel bad and you feel good all the time.
Edit: In light of a few comments and questions, i'd like to clear something up...
It's not about trying to feel good all the time. It's not about trying to feel anything. The idea is to stop giving meaning to situations so that you can experience the situation instead of the stories and feelings you create about it. Contrary to the title, it's not even about making a choice to feel good. The choice is to stop layering things over true experience, and that feels good. A whole lot better than manufactured good feeling.
Choose to not be controlled by your stories.
Choose to stop giving meaning to things.
Feeling good is a choice.
Make that choice.