Comfort and Convenience
Cabin temperature is the preference people disagree about most often. Someone in the back may want more air while the driver is already comfortable, and body size, clothing and sun through the glass all shift where the ideal setting sits.
Safety and Driver Assistance
It is worth a minute in a stationary car to find the lights, wipers, demister and hazard switches. Doing that before setting off means an unfamiliar situation on the road is not also a first search.
Multimedia and Connectivity
On longer trips the phone battery is usually what runs down first, particularly with navigation running. If a charging point is available and within a passenger's reach, the phone can be topped up without being handed around.