What mistakes have you made along your founder journey

I just wrote a new Substack post about habits PhDs bring from the lab that can lead to mistakes that derail their startups (https://buildingfor2075.substack.com/).

It got me thinking about the mistakes I made in my career as a founder. I think my biggest mistake is holding out too long on an idea or situation that isn't working. I don't like giving up, but sometimes it's the best thing to do. It might be an engineering solution, a team member who isn't a good fit, or waiting for a customer to engage. I've started getting better at setting more specific, time-bound goals to help me know when to call it, but it's still a challenge.

Curious what other challenges people have discovered along their journey and what they did to overcome them.