It would be nice if there was a way to communicate with other drivers in a less one-dimensional way by having a "friendly" horn sound option. A really good example is this video:
I drive more quickly and fluently on the roads I know well.
Can something similar help the autopilot? Remember or share all roads and compare it with what you see. Horn when anything is different.
Instead of the horn honk as the vehicle locking sound, allow the use of the Boombox speaker for something more pleasant.
For example, the Rivian makes a bird chirping sound when you lock it.
How about a quiet honk to warn pedestrians or cyclists that you come up behind. Perhaps a tap on the end of the drive selector at beow 5mph? A normal honk gives them a fright!