not a stupid question but i got sacked the other week from a customer i had been clenaing a year.
Car was on the drive, which ive never seen before..
cleaned it, 10 mins later text message, "we would like to cancel our window cleaning, you have left them full of water and not dried it off, i wanst aware you had been doing half a job all this time, i thought we were paying for a proper service"
or words to that effect.
needles to say the most annoying question is why havent you dried them off