Gardener, gardeners, builders difficult to do without such a vehicle, like a car. When moving a wide variety of goods it greatly facilitates the hard work — saves energy, time, and possibly health when the volume of traffic is significant. In the markets of construction materials and are sold in hozmage cars of various designs. But at a price that is incomparable in their efficiency. Besides, they are made according to the type of commercial trucks with the wheel in front of the loading platform (or body).
As we know from school physics course, such a system forms a lever of the second kind. So almost half the mass of the load falls on the hand pulling. If you try to lift most of the weight on the fulcrum (wheel) lifting above the handle, then push the cart becomes much more difficult.
To unload a car rollover forward is also easy, as the whole mass has to transship through a fulcrum (the wheel). Dumping the same load on the side creates such bending (twisting) moments in the frame of the cart to which it was not designed.