What are Your Biggest Challenges as a Founder?

I am researching how to best help startup founders, and tools available for early-stage business problems. If you have time, please answer:

1. What have been the hardest problems to solve since deciding to go into business?
2. What solutions did you use to solve those problems?
3. What's a solution you wish existed to make solving those problems easier?
4. Would you pay for any of the solutions you imagined in 3? If so, how much for each of them?

Bonus: If you read this thread and know of a tool that answers problems mentioned in other people's #2 and #3 that haven't been surfaced, please call them out! (I've personally tried over a dozen new tools in the last month, and imagine I and everyone here is always on the looking for more that are good.)

Thank you!