How do I deal wtih not doing anything because I don't finishing things?

[Parki]

I am basically afraid of starting any project or anything like that because if I don't finish it, it will be a huge waste of time.
Please don't bring the "But even if you didn't finish it, you still learn something from it etc".
Yes, it is a thing, I will gain something even if I spectacularly fail, but in this context it doesn't matter.

It feels like lifting something very heavy to put at a high shelf, if I don't lift it enough I need to start again.
There is always this thing "If it's not going to be finished, there is no point in starting it. Start only if you are going to finish it. I know I am not going to finish it, so I don't start.

This text is a very good example of it. I try to understand how it works, I put some effort and if I didn't get to the bottom of it, all the effort of me writing this text will be wasted.

ps I see it's poorly asked question, but if I don't post, it's even worse, you know why.

[PurpleTree]

could be fear of failing, could be perfectionism, could be add/adhd, could be something else

 i wanted to write some more but then i didn't feel like finishing it  

[romansoloviov]

Well, sometimes you don't know whether something is worth finishing until you start it