What's the hardest thing about being a solo founder?

What do you struggle with the most, and when do you wish you had a cofounder? Do you find that having a network helps?

I think the hardest is that you're on your own and there's not many people to mirror yourself to. Communities like this make it easier because at least you have people with the same ambition in a group.

I left Amsterdam years ago and even there it was hard to find a community of people really making stuff and building it into businesses.

No buddy to discuss the product seriously. I have ever experienced to build both lonely and together. In fact, it's faster to build lonely than together. But the issue occurs when facing the serious problem. I want to discuss someone seriously.