Occasionally Triple Crowns are the result of inferior competition (we say "occasionally" and "inferior" with a big ol' tongue in cheek—the last hitter to win the Triple Crown did so 45 years ago). Maybe one year home runs are down across the league and you pick up that leg of the trifecta cheap; maybe a slugger has a career batting average year and wins that title in a squeaker. But when you win the Triple Crown across both leagues, there's no denying you were the best hitter in the world that year. Mickey Mantle hit .353, clubbed 52 home runs and knocked in 130 RBIs in 1956, numbers that would've put him atop the leaderboard in the American League, the National League, and any other league that kept track of those accomplishments that year. Of the 16 all-time major league Triple Crowns, only five were "Major League" Triple Crowns. And two of those were accomplished by Yankees.
16. Mickey Mantle Completes the Triple Crown