Fair vs. Fun

TLDR; If you have to choose whether a game should be more fair or more fun to play, which do you choose?

Recent discussions about whether Riot balances the game more for professional or hobbyist players makes me curious about how League of Legends players (and developers, if they feel comfortable posting their opinion publicly) weigh this fundamental game design tug-of-war.

For some, they are one and the same, of course. Competitive players need the game to be fair before it can be fun. Trolls have fun by subverting the fairness of the game. But I suspect most players (and developers) prefer to balance both so neither is lacking.

But sometimes, such a balance isn't possible. Suppose you have to choose between a game mechanic that will make your game more fair but less fun or another that will make it less fair but more fun. There is no middle ground nor is there the option avoid the choice.

In such a circumstance, which would you choose?