A few rapid fire ideas.

Don't rule out medication. It can be the thing that lets you get over the first hurdle so you see what it's like on the other side.

Go for variety. I'm a software engineer but I am doing very physical and mechanical things in the evenings, at least until winter. Then I can do some tech shit

Be intentional with your time and resources. Think about what benefits the journey of your project will have for your personal well being. Being conscious of the benefits of an activity lowers the the threshold for the effect of "just push through and then you get used to working on it and keep going and now it's your hyper focus."

Own your decisions and keep them to yourself at first if you have to. If it's a hobby you're interested in, you will probably do a good job learning and you will produce good results, and that will help build the kind of deep fundamental confidence that you can't just decide to have.

I am very much an ADHD + Rejection Sensitive Dysphoria type. There's a related issue called Avoidant Personality Disorder. I have gone nuts on my conduction projects for my hobbies without constantly including family and friends like is typical in my circles when doing big yard projects.

So while my advice inevitably will not work for everybody -- we're all different and we have to reverse engineer our own brain & body manuals -- hopefully some of this will make sense in this case.

Soo.. everyone is giving you advice to help you "overcome" this tendency. I disagree with them all ! First of all I am the same as you, but I have come to realise that finishing projects doesn't fulfill me or bring me any joy. Quite the opposite, when I finish a project, the end of the project is very boring, a lot of work, and once done I just feel empty and drained, I'm just glad I can finally stop. What brings me joy though is starting a project, learning new stuff required for that new project, all that initial phase of the project is the best feeling, I'm hyper focused, I'm in a trance-like state, I have millions of ideas and thoughts about it, then once I figure out how to do it, I slowly abandon it and I don't want to finish it and that's ok, I'm happy because I'm doing the best part (imo): learning how to do it, figuring it out, proof of concept.

If you are like me, don't listen to all the people pushing you to finish, they don't get it. Do what you like. We don't have to be productive in all our endeavours, just having fun while it lasts is ok.

In my case this behavior turned out to be an avoidant coping strategy for handling my fear of failure. If I don’t work on it, I can’t fail (or be judged on its end result), thus I’m safe. That’s level 1. Level 2 is to ask, why do I fear failure in hobby projects?

Another aspect is that because it’s all for fun, often the fun parts for me are the initial design and the process of figuring out that, yes this idea would totally work! The actual work of the implementation is the less fun part so I’m less interested in doing it.

TLDR: talk to a therapist about it, they can help you map out what’s happening, and by becoming self aware of the cause, you gain power over it.

The most successful people don't have goals they have constraints.

Here's a really good one, don't start another project until you've finished the last one UNLESS it directly relates to it. in this way even without a clear goal you are always building towards something and with a narrower field you're more likely to accidentally finish something as different projects converge.

Just start a new small project when you lack the energy to continue your current project. Chances are, you finish the small project, release the dopamine nesessary to continue, and then you may finish your old project.

There's also helgrind if you're doing multi-thread. Man that will slow things down a lot.

Exactly.