Typically it is tougher on the car to let it sit still and warm up. On all but the coldest of days one should try to drive it to put a load on the system. The load will get the engine warmed up faster. You should not hit it while it is still cold but it is better to drive then to let it sit. Letting it sit means it takes longer to warm up then necessary and starve those cylinders of necessary lubricate
