One of the reasons I don't use the autopilot that much in my Model S is that it is trying to be "too perfect", in the sense that it seems to want to stay right in the middle of the lane.

You may be thinking: why would that be bad? It seems like a reasonable approach.

It is reasonable, but not good enough.

In the Bay Area, potholes abound, and the car - if left to its own driving style - will happily go over every single one of them. Same if there is any hazard on the road (tires, debris, etc): no avoidance at all.

The second thing is that it will not adapt to lane sharing traffic: the car will happily go back to center, even though a motorcycle may be passing it to the side. Even if the sensors detect it, it's still a bad scare for the motorcyclist who will believe that I tried to run him/her over.

At the end of the day, I end up having to take over too frequently to be very useful. The cognitive load of maintaining a lane is so small that it doesn't feel like offloading it is a big benefit.

Once we reach full autonomy (with an algorithm that minimizes damage to the car from potholes and other elements), it'll be different I think.