Thank you for writing. You are right, of course. Not being able to commit to anything is a sure fire way to kill a passion when it barely starts.
It’s possible that your analysis is correct — that you don’t believe in results. But I have another point of view. I suspect you are scared that the result of effort will be failure. An effective way to avoid failure is to not even try. You can then say to yourself, “well, if I tried, if I stuck with it, I’d be great at it.” It’s a common way that people who are phobic about failure protect their self-esteem.
If we were talking together, I’d ask you why failing at something is so difficult for you. Maybe you don’t know that sometimes failing at our best efforts is important. Sometimes it means that the activity or interest isn’t really worth pursuing. Sometimes it’s an important moment of learning.
Thomas Edison failed in thousands of attempts to invent a lightbulb. When someone pointed it out, he is said to have replied that he knew 1000 ways to not make a lightbulb. He learned from each attempt. He tried and tried again until he found a method that worked.
I often tell that story to help people understand that unless they experiment with something that most would agree is a big mistake (like drugs, crime, self-injury, pregnancy, etc.), trying out new things generally won’t kill you. Yes, failure sometimes hurts or disappoints. But it isn’t generally lethal — and chances are you will learn something important.
The teen years are an important time of experimentation. You are supposed to be trying out different interests and activities. You are supposed to discard some of your “passions” as you find others that are a better fit. The trying and deciding is how you will discover your career goal and your life direction. It’s how you will decide what kind of schooling or experience you need to accomplish those career goals. Trying out romance a few times will help you figure out what kind of person you want to spend your life with. Trying out getting to know different people will help you decide the friendships you most value and who accepts you for yourself.
If you want to nudge yourself out of your habit of withdrawing from things, do an experiment. Commit to sticking with something you think you’ll like for 3 months. See what happens. Think about what you are learning along the way.
If that doesn’t help, do consider seeing a therapist to talk to you in more depth than I can in a letter. It’s also possible that I’m way off base. A therapist will help you understand the origin of your “terrible cycle” and will provide advice and support in your efforts to break it.
I wish you well.