Jim, you could ask the same question about the atmosphere. The pressure at the surface is 14.7 psi - a weight equivalent to over ten stone on your palm. So why don't we feel it?
The answer comes from Newton's Third Law - the action and reaction one. My chair has four legs with a base surface area of about 4 square inches. Me and the chair weigh 180lbs: the pressure on the floor is therefore 45psi, about three atmospheres. But the reaction of the floor supporting this force is the same - it must be, the chair's not sinking into the floor. Likewise with your hand - the pressure on all sides is 1atm, but there's a counter pressure of 1atm at the skin due to the (relative) incompressibility of humans.
The car in the boggy field sinks, as the counter pressure of the mud is mechanically not able to support the vehicle's weight (...but it might if the pressure was reduced by spreading the weight over a larger area: give the vehicle tracks to spread the load).
At the bottom of the ocean, where pressures can be over a thousand atmospheres, the waterlogged silts (effectively incompressible) provide a counter-acting supporting force.
Andy