I realize it's not football season but I always wondered about these things from the Super Bowl.
When the Patriots intercepted the Seahawks' pass at the end of the game, the announcers said that they had to retain possession of the ball and get it out of the end zone. This makes sense, otherwise Seahawks would get the ball back and score a touchdown or safety. When they got the ball out, everyone stopped playing with about 20 seconds left on the clock. Why does this happen? Did the Seahawks give up? Is this what "taking a knee" is? Why not fight until the bitter end? There is still a chance of a fumble, interception, or safety just like when they were 1 yard behind the end zone, right?
Also, when games are close with a minute or two left, the announcers always say "Tom Brady/Peyton Manning are always a threat to drive all the way down the field with a minute left". If they are so good at scoring all the way down the field in such little time, why can't they do this in the beginning of the game? Why do some games go scoreless in the first half, then all of a sudden they can score at will at the flip of a switch with a minute left in the game? Why can't they score 60 times in a game then?