Best first aid kit in the world isn't worth a crap if you have no idea what all that sh!t is for. 
Funny side note. Last weekend I took my cert course for Swiftwater rescue. Unfortunately one of our guys way injured when he clipped a rock and split his knee open performing a rescue.
Picture, if you will, 12 students completely focused on the task of saving lives, and not a first aid kit in the group. They all got left at our vehicles nearly a mile downriver.
(for the record I now keep mine in an otter box in my PFD pocket)