That's what you get for paying out previously-collected fees when people land on "free parking," failing to auction off property that the person who first landed on it didn't want, or using other house rules to try to make Monopoly "fair" and "fun."
If the first person who gets lucky enough to complete a property group doesn't quickly and ruthlessly grind his opponents down into bankruptcy and make them hate both the game and capitalism itself, you're doing it wrong.