you can't mend the coffee grinder when you are meditating

Have you noticed how your mind does things when the thing isn't there?  Sometimes it seems useful, say when you are driving along and you replan your house/wardrobe/diary! but this habit of drifting into a future which doesn't exist follows you straight through the door of meditation and there you have to be determined to stay focussed on your practice and not try to mend the coffee grinder until later.