From $1-$100k in ARR, the hardest part is often how little revenue you get from each customer.From $100k-$1m in ARR, the hardest part is how slow it is.From $1m-$10m in ARR, the hardest part is you don’t have enough people or patience.At $1B+ ARR, the hardest part is you have to be so Multi-Product that you are really running 2-5 SaaS companies.