You want to lose weight but eat midnight snacks every day, isn't that the opposite of your goal?
Tips
history
From 《战国策·魏策四》: a man tells Ji Liang he's driving his carriage to Chu (southern state), but he's heading north. When warned, he boasts about his fast horses, ample money, and skilled driver. Ji Liang replies that the better these are, the further from Chu he'll end up. The tale cemented the idiom's meaning.
memory
辕 is the cart's shaft (pointing the direction of travel); 辙 is the wheel rut (the path actually taken). Shafts aimed south, ruts running north: the wrong direction is built into the cart itself.