6. Greg Norman vs. Tim Finchem
Norman and Finchem, the PGA Tour commissioner, first butted heads in 1994 after Norman announced plans for his World Golf Tour. Finchem quickly torpedoed the deal, lining up A-list players to denounce the idea. Three years later, Finchem started his own iteration of Norman's brainchild — the World Golf Championships — leading Norman to threaten to sue the Tour to force it to reveal its financials to its membership. "Never will I forgive Tim Finchem," Norman said in 2004, "even if he inducts me into a Hall of Fame once a week."