Front-wheel drive (FWD)
FWD is the most common drivetrain layout, and it's pretty self-explanatory: with the exception of braking, the rear tires are mostly along for the ride in a FWD vehicle, while the fronts do almost everything. In cars with lots of power, the wheels are sometimes pulled to the left or right by the sheer torque of the engine. This is something called torque steer, and if you floor your car and pay very close attention to the steering wheel, there’s a good chance you’ll feel it in your car. Sure, with modern engineering, some FWD vehicles are quite good.
FWD offers some advantages over RWD in snow, since the weight of the engine pushes down on the wheels, but in normal conditions it’s still a compromised set-up from a physics standpoint.
Why does it exist in the first place, and why is it so popular? Well, in the beginning, it was cheap. It’s far easier for a manufacturer to assemble a FWD engine/transmission combo and simply load it into a car on the assembly line, whereas the other drivetrains require a special tunnel running through the center of the car. It’s also lighter, which means better fuel economy -- during FWD’s rise to prominence in the years surrounding the gas crisis, that was kind of a big deal.