For the uninitiated: the bulk of the Top Chef season is shot over six grueling weeks some months before the show airs (up until the finale, which is shot as the early episodes air.) While we're shooting, I have very little contact with the contestants beyond those filmed kitchen forays where the chefs struggle to stay friendly to me as they're quietly freaking out, the rare interaction during a challenge (like my bout as expediter at Tramonto), and the couple of minutes it takes for us to taste the food, and share our judgment with them at the Judges' Table. We see tape of the chefs' interviews, and clips of them cooking, bonding, or fighting only after they've been cut into the final episode. It's thus impossible for us to draw anything other than the most cursory conclusions about the chefs, much less figure out ratings that don't yet exist, or who will eventually be "villain" or fan favorite.
If we had been able to somehow able to figure this out ahead of time and thereby act upon it, Tiffani would have been booted early in Season One (or Stephen, take your pick), Marcel would have never made it to the head-shaving incident, Sam would have won Season Two hands down on the female vote alone, and Tre would have stayed, despite screwing up, because he was such a likable and competent guy. In fact, we would have been compelled to ignore all of his subsequent mistakes because he had been such an able contender up to that point.