Then they will just accept ur letter of resignation, cause lets face how many people are irreplacable? If u want to put ur point forward have facts and hard evidence to back it up, Not i think or my mate says type stuff, facts and figures. Show them how u can increase productivity while keeping cost the same or even reducing them. Then u can use the words, Im sorry for attempting to increase our productivity and reduce our costs i wont do this again, Please let me extend my formal appology to yourself.