[Denny_A]

I concur with previous comments, and add an example from aviation - regarding limitations.

Pilots are constantly taught that their planes can perform fine at a calculated max takeoff weight for elevation, temp, etc. They'll dutifully acknowledge the theory during instruction in the classroom and in the flight simulator. But, put a full load of passengers and baggage on the plane, raise the air temp so that the plane is AT max takeoff weight- and they start to sweat bullets. Theory meets reality. Even though the charts allow a takeoff, it doesn't "feel" right. What if an engine hiccupped at rotation. And so on.

Same process (w/out paying pax) applies when a trailer is towed at or a little above capacity. Stopping distances increase disproportionately due to brake energy needed. Transmission and engine wear increases, and so on. If the driver is aware of some, or all the effects, he/she can't help regularly worrying about something going wrong.

Which is exactly why I traded my Honda Odyssey (3500 lb tow limit) for a Toyota 4Runner. PEACE of MIND! It requires excess capacity from the tow vehicle to be a carefree camper. A tow limit of at least 5000 lbs will handle almost every TM made (3326 would be a stretch). The 4Runner (5000 lbs. tow limit) has set me free. Especially in the hills, on steep grades. No worries!

HTH - Denny_A