Damn! Why finishing stuff is so hard?

For me it often comes down to the 80/20 principle. It only takes 20% of the time to get a product 80% done. It takes the most amount of time to finish that last 20%.

A trick that has worked for me is to ship an 85% finished product.

Maybe it's because a product is never really finished?

I think you need to be very clear from the beginning on what goes in the current version of the product you're developing. I use Trello to manage my tickets and I have two columns: Current version and Next version.

I put everything I don't need for the current version in the next version column.

How do you know what functionality you need for the current version? Well, you need a global strategy: the first version will do this because of that, the second version will do that because of this, and so on.

Be ruthless. Don't add hundred of tickets in the current version column. You should define them in advance and touch them as less as you can. Authorize yourself to break down tickets, but not adding new one.

If it can help I wrote some article about side projects:

1. The mindset to start and finish your side projects: https://thevaluable.dev/side-project-successful/
2. The tools to start and finish your side projects: https://thevaluable.dev/side-project-tools-practices/

The thing is only you can answer this question. You need to find out what you do when you are not doing what you want to do. And then you need to find out why you are doing it.
You can also check the blog I wrote. It can give you some ideas about what can help you
http://alexmartynov.com/en/how-to-unstuck-the-change/

This video by John Sonmez has helped me a lot https://www.youtube.com/watch?v=YC4K-mikkj4

Because we all like learning and playing with new stuff. So when we are at the end of work, nothing is new for us now.

Your frustration might come from not realising that 'stuff' as you put it is never finished.

Can you name one company that's.... finished?

For me, realising that there is no end; there is no finish line; it's never going to be done was like the aha! moment my moral needed.

@Cosme12 - that's exactly one of the things I was trying to find myself in an earlier post here @ https://www.indiehackers.com/STARTUPHUBS/post/fa4ee5b6c5

Got a few suggestions there and hopefully when I talk to @AlexMartynov for self-reflection and guided inquiry I'll learn more. :)

This might not have answered your question but hoping would give you a few pointers.