The faff involved in adjusting the instrument and radio brightness at night. If the lights are on during the day (rain etc) or have just come on for dusk, I like the lights up to the max as it keeps the instruments nice and clear to see. When it's finally dark outside, I like to dim the interior lights down to ~30/40%, to keep the ambient in tune with the time of day.
Why isn't there a dial next to the light switch to allow me to do this quickly, with out having to select "Car=>Settings=>Lights=>Instrument" and then adjusting the brightness?