In a strange 24-21 game Sunday, for example, the winners were the 6-1 Tennessee Titans, who led in the first quarter, 21-0, but scored only three additional points.
St. Louis Rams, were the better team.
In the end, after three touchdown passes by quarterback Kurt Warner, the Rams got to within a missed 38-yard field goal of overtime.
For Warner, it was all a learning experience.
As an NFL player, he'd be classed as a rookie this year if he hadn't sat on the Ram bench last year; and in Sunday's first quarter, when he lost the ball twice on fumbles, Warner often played like any other rookie quarterback.
For the first time in his life, he was facing the kind of powerful, hostile pass rush he never saw in the Arena League or even in NFL Europe.
You can only learn how a rush like that feels by getting it, and Warner got it.
His three touchdown passes came next.
And in the final minutes, he led the Ram field-goal drive that had everything but a field goal.
One Great Quarter for McNair
The winning quarterback in the Rams-Titans game, Steve McNair, played all of his good football in the first quarter. Coming back from injury, McNair ran and passed Tennessee 80 yards to its first touchdown and earned two more touchdowns after turnovers.
Fumbling twice in two minutes, the Rams' Warner was blindsided into his first misplay, when he was sacked and stripped of the ball.
That happens to all quarterbacks but, in time, after some seasoning against NFL blitzers, the better quarterbacks develop a feel for the backside rush.
Warner hasn't yet had much of that kind of experience. Indeed, until Sunday, he hadn't had any.
On the Rams' second fumble, Warner handed off toward a new fullback who missed the signal and was, instead, about to throw a block.
Although that sort of thing also happens to good, new, young teams, it wasn't turnovers that beat the Rams, it was McNair.