His bobbled snap against Seattle in the 2006 playoffs will always be remembered.
Why? That has nothing to do with quarterbacking. And even if he'd not bobbled the snap and gotten the field goal, plenty of time for the Seahawks and Wilson to drive down the field for a field goal to win the game, and who doesn't believe that was a distinct possibility? Just another bad play that people point to as a Romo criticism, which wasn't a game ending int (which Romo had, let's not forget) or such, did hurt the chances of a win but didn't totally cause the loss.
See that's the thing about Romo that endears him to the fans. He loved the game, loved playing for the Cowboys, and would do anything he could to help the team. He probably could have gotten out of the holder job, or may have even asked to be the holder, so as to help the team.
And the last thing was a big part of his playoff "failures". If there was a chance he could make a big play, the big throw, or the big run, to win the game he tried to do it. Rather than take a sack, and hope the defense could get a stop so the offense could get another crack at a score, if he saw a tiny crack in the defense and could squeeze a pass in for a first down, his instinct was to "go for it". In other words, he played to win. Did he overestimate his abilities to do that? Sure, in many cases.
But in the heat of the moment, needing a split second decision, there's no time for deep, reflective analysis, your instinct takes over. Was it a good decision for Eli to throw the ball up for grabs to the top notch, all time great (satire here) David Tyree? No, but Tyree made a one in a lifetime "helmet catch" and there were able to win a SB in part because of that catch. Call it instinct or desperation, the catch was mostly luck. Romo didn't have that luck in too many cases.
Romo did his best to win, that's what he'll be remembered for, at least as far as my memory will be...