But if there's one team capable of a postseason comeback, it's the Red Sox, who've made playing from behind almost habit-forming.
In 2003, they dropped the first two games of the American League Division Series to the Oakland A's, then ripped off three consecutive wins to advance to the ALCS.
In 2004, they fell behind the New York Yankees three games to none in the ALCS, then staged the most improbable comeback in postseason history.
Now, having lost the first two games at U.S. Cellular Field, the Red Sox must do it once more.
No margin for error. No games to give. Win or else.
"It helps [that we've done it before]," said Kevin Millar after the Red Sox suffered a crushing 5-4 loss on Wednesday night. "But you don't want to make a living at it."
That's precisely what the Red Sox have done the last two postseasons. No doubt, that institutional memory comes in handy for most of the players. Of the nine position players who started Game 1 against the White Sox, only the double-play combination of Edgar Renteria and Tony Graffanino didn't experience the comeback over the Yankees last October.
The impossible doesn't seem so daunting when you've already accomplished it before -- in some cases, twice.
"We've got to win three in a row,'' said Curt Schilling, who would start Game 4 if the Red Sox can get that far. "It's not like we're saying we've got to make pigs fly. We've done this before."
But what makes this attempt more problematic is that the Red Sox lack the pitching depth -- both in the rotation and the bullpen -- that they had last year. Whereas the Sox boasted co-aces last year (a healthy Schilling and Pedro Martinez), this year's rotation is far less dominant.
Moreover, the bullpen isn't nearly as dependable. Last October, Keith Foulke pitched three consecutive games as the Sox began their uphill climb against the Yankees. This fall, Foulke is sidelined and the bullpen is thin; only Mike Timlin and Jonathan Papelbon have the full confidence of manager Terry Francona.
But if intangibles count for anything -- and the Red Sox have to hope they do, especially given the White Sox's relative inexperience in the postseason -- the Red Sox have the edge.
"It's not a pattern you want to fall into," Boston general manager Theo Epstein said. "But over and over and over again, this team has played its best baseball with its backs against the wall. It's the personality of this club. We tend not to do things easily."
For their part, the White Sox, who haven't won a postseason series since the 1917 World Series, don't want to give the Red Sox the opportunity to get back into the series. Manager Ozzie Guillen had closer Bobby Jenks in for a six-out save Wednesday night in Game 2, intent on claiming a 2-0 advantage.
Guillen has already emphasized the need to play with urgency.
"You have to get this over as soon as you can. If not, you're going to be in trouble," Guillen said Thursday.
But first things first. If they go down, it won't be for lack of confidence.
"There's not even a thought in my head that this team will get down on itself," Epstein said.
"This clubhouse," Schilling said, "is the same all the time. There is no letdown. We'll show up [tomorrow] and we'll do everything humanly possible to win that game."
"This is a crazy group of guys," Millar said. "Backs against the wall? Our backs are scraping the wall and we're almost on fire. But it is what it is now. We're either going to win three in a row or we're going to watch the World Series at home. It's as simple as that."
Sean McAdam of The Providence (R.I.) Journal covers baseball for ESPN.com.