There's a huge difference between being worth $10M on paper and having $3M sitting in your bank account. Founders usually understand this after their 1st exit.. A high valuation feels awesome. But you unfortunately can't buy a house with it. You can't invest it either. You can't use it to fund your next startup. Plus there's no guarantee you'll ever turn that valuation into cash. Then you sell a company and the wire finally hits. Suddenly you have real money that can compound for…