This card worries me when I see it, because in most of the decks that I'm familiar with, the chariot driver is either barely in control of the horses, or not in control at all (like the Barbara Walker deck, which depicts the chariot as having no reins and the horses heading in opposite directions). To me, this represents overconfidence, or an illusion of control -- you think you know what you're doing, but your grip on things isn't as firm as you'd like to think.