I have my commercial driver's license. Driving an 18 wheeler is an order of magnitude harder, but even that is not too hard once you know the constraining rules. I think it is harder to stay in a minimum width lane than it is to shift an 8 speed with 3 splitters and no synchromesh. The rev band is only around 2k RPM, and you only have around a 200 RPM window, with a 50 RPM sweet spot, where the gears will engage without grinding or shutting out the gate entirely. Cars are quite easy by comparison. Driving a tractor trailer, then getting into a regular manual car makes the car seem laughable. It really isn't hard at all.