People tend to like to think there was one cause and only one cause for an interception. Quite frequently, though, they are the result of many things. Take the pick Charles Woodson made in the opener off Geno Smith.
Factor 1: Charles Woodson read Geno Smith's eyes and started breaking on the ball.
Factor 2: Geno Smith gave away where he was going with the ball around a full second before he threw it.
Here's where Woodson was when he started breaking for the ball. Geno's eyes are on Decker give or take a second before the ball comes out.
This is where Woodson is give or take a second before the ball arrives. This is probably where he would have been when the ball arrived had he not gotten a head start. It's also around the time the ball is coming out. He has made up a fair amount of distance as the ball is just beginning its flight because of the way he read the eyes of the quarterback prethrow.
The head start he got because he read the quarterback's eyes made the difference in the interception.
Part of it is a really nice play. Part of it was the quarterback giving him a head start on the opportunity to make a play like that. I would also add:
Factor 3: Eric Decker could have come back to the ball, although I can forgive this more because he isn't anticipating Woodson coming from where he comes.
This, however, is the kind of mistake that loses games and something Geno really needs to clean up. Telegraphed passes result in turnovers. You can tip your cap to a great player making a great play, but everybody knew Woodson was playing in this game. There's no reason to assist a great player, and this was one of the low points in the mixed bag that was the opener for New York's second year quarterback.