Fog basically means no wind or turbulence. So, smooth landings would be expected and easy. More challenging would be lots of cross wind, wind shear, and turbulence. The plane basically has to land at an angle and then yaw to straighten out at the last second all while constantly correcting for changes in lift and vertical speed. So you are shaking around the plane and passengers quite a bit.
A rough landing is actually considered a safe landing when the conditions are not ideal. A smooth landing means flying the plane close to stall speed. So close that it gently touches down with barely any vertical speed left. You don't do that when there's any risk of wind shear causing very sudden and extreme drops in air speed of tens of knots. If that happens you drop below stall speed and basically the plane drops out of the sky. If that happens low enough, you crash and die. It's extremely unsafe to do anything else than plonking it down decisively under such conditions. That means a larger vertical and horizontal speed and eliminating airspeed via the shock absorbers instead of floating over the runway. That's what shock absorbers are for. As long as the plane doesn't bounce off again, it's all good. Bouncing is dangerous though because now you are slow and stalling.
A rough landing is actually considered a safe landing when the conditions are not ideal. A smooth landing means flying the plane close to stall speed. So close that it gently touches down with barely any vertical speed left. You don't do that when there's any risk of wind shear causing very sudden and extreme drops in air speed of tens of knots. If that happens you drop below stall speed and basically the plane drops out of the sky. If that happens low enough, you crash and die. It's extremely unsafe to do anything else than plonking it down decisively under such conditions. That means a larger vertical and horizontal speed and eliminating airspeed via the shock absorbers instead of floating over the runway. That's what shock absorbers are for. As long as the plane doesn't bounce off again, it's all good. Bouncing is dangerous though because now you are slow and stalling.