The replays are necessary because fans and media are mostly unreasonable. It's a little ironic to me to complain about replay in the same thread that people are complaining about calls. We want to get the calls right, right? So who cares how long it takes? Just get the call right.
No single officiating call can cost you anything (although multiple gaffes can certainly cost you, see: OU-Oregon in 2007).
I grew up a big baseball fan (less so these days) but the first time I truly fell in love with a team was the Cardinals...in 1985. For some of you, I shouldn't have to say one more word but for the rest of you, I will.
Don Denkinger made what is probably (maybe even inarguably) the worst call in the history of modern baseball. If so, it's the worst because it happened with the Cards right on the cusp of winning the World Series in Game 6 (up 3 games to 2), in the 9th inning of a game they were winning...a World Series they would go on to lose to the craptastic Royals.
The moral to the story is, from 1985 (age 10 for me) to probably age 25 or thereabouts, I fully blamed Don Denkinger for the Cards losing that World Series.
But the bottom line is, after I fully grew up, it's pretty damn obvious they had a ton of opportunities, otherwise, to win that World Series. And if I can come to terms with this bad call...or even the awful call in the Texas game in 1984...blaming officials, refs, umpires...it's what sore losers do. You create your own luck, you create your own opportunities and you either win the game for yourself or you lose it for yourself. Nobody else does it to you.
There's nothing more annoying for me than harping on a call. Now, I understand general criticism, say one football team had a STACK of penalties and the other team had very few, and just happened to be the home team or something. Or one team had a TON more fouls than another in basketball. That's a general criticism that makes sense. But this idea that (for instance) the charge vs Arizona last night cost them the game or something - that's nonsense. There are tons of missed opportunities for either team all game long.
ALL THAT SAID, there are very rare situations where officiating is actually so egregiously bad that one error is compounded by more than one. Don Denkinger missed one call at first base. That, in retrospect, even for this Cardinal fan, and if not taken in isolation, didn't cost the Cardinals the '85 World Series. But the Oregon F-up, where an INSTANT REPLAY official with a chance to correct an on-field mistake - missed THREE separate issues in order to uphold the call on the field...yes, that's an officiating blunder for the ages. An all timer. And yes, there is no question it cost OU the game.
