This may sound like a dumb question but, why is it that whenever i see players shoot at an enemy its always behind them like 2 feet. But whenever i shoot in order to hit i have to aim directly on them? I also see this with a scout or an awp.

Not really a dumb question. It's due to the netcode and a small bug when spectating someone playing. There's a little lag you experience when viewing someone while they're playing so that it may look like they're shooting behind the target. The best way to view someone playing is from the personal demo recorded by the player that you're spectating.

It is for this reason that most online leagues require you to record a demo while playing a match so that if a dispute arises they can watch your demo which should be free of any extra lag.