It's more of what works in the game but doesn't work in real life. In Madden an old glitch that has since been fixed is that whenever the Quarterback would break the pocket, the receivers would break their route. And when they broke their route the receivers would go to the same spot every single time (towards the sideline). But at the same time, the DB's would get confuse which would then leave the receiver wide open. This would happen EVERY SINGLE TIME. So you would have wide open receivers no matter if the defense was in zone or in man.

Every football player knows that the db's would be looking for this in real life and would step up and stop the play after one or two times of this happening. But in the old versions of Madden the corner back would not learn and you had an open man every time. The only way to stop this was to have a team with a good blitzing line backer or defensive end and hope he gets to the QB in time. (This glitch made McNabb almost unstoppable in several versions of Madden.)

Another problem in the old Maddens was that if you had the tight end lined up on the left and had him go up five yards and then had him cut left quickly then if the defense was in man he would get the ball every time. And when the defense was in zone he would probably get the ball 70% of the time. In real life a highly skilled LB would be able to stop a sub par TE on this play. Just by being faster. But in the world of Madden the worst TE would get a completion against anyone.

These and the other tricks I would use were effective in Madden versions 97-03. The AI is much better now but there are still glitches. I just don't play it enough anymore to have figured them out. Others have though.