When you are working too long on your side project what are the biggest issues are you dealing with?

I've had different experience in the past.

At the beginning I used to delay the launch for too long thinking that the product is not good enough. Later I managed to overcome my perfectionism.

However, on another project we spent two years tweaking the game to make it engaging and profitable, but still didn't reach good KPIs and decided to kill it off.

What is your experience? And if there was a magic wand what problem would you like to resolve when working too long on your side project?