Given that most of us think we are above-average drivers, you’d think people wouldn’t expect other drivers to be telepathic.
Turn signals prevent other drivers from hitting you! (Or at least reduce the chances of it.)
I am amazed time and time again as I see people driving shiny new Mercedes, Lexuses (Lexi?), and BMWs dodging in and out of traffic without signalling, trusting those below-average other drivers to have above-average reflexes and precognitive abilities.