Another would be professional poker player, an idea I toyed with for awhile. You have customers in the same way sharks have customers. Every other person at t

Another would be professional poker player, an idea I toyed with for awhile. You have customers in the same way sharks have customers. Every other person at the table could hate your guts (though that's not optimal), but they'll still sit there and give you money, provided you're sufficiently skilled. The two professions are pretty similar - they both involve a zero sum game you're playing against other people.