"I have NEVER met a motivated person who has said they would not chase their goals because of tax rates" This is a common mistake that Cuban makes. The problem with taxes is that they affect marginal behavior. The doctor works a little less, and entrepreneur sells out a little earlier, the medium business hires one less worker than they otherwise would have. These decisions are invisible because they are small and we can't compare what is to what would have been. But, the costs of taxes on economic efficiency are real. We need taxes for to pay for government. And, we can debate how big magnitude of the distortionary effect of taxes. But this should be done with data not based on anecdotal feelings.