Title. Pisses me off mildly. I’ve got my earbud in for a reason (quick drive) and Bluetooth decides to connect to the car when it starts. The cars’ head unit takes forever to start and have to manually switch over to Bluetooth mode (while the audio is already playing) and the volume is way down.
And when you get out of the car it doesn’t automatically connect back to the earbuds.
Depending on where you live, you could be breaking the law. In the USA, doing that in some states is illegal. See here.