If you feel that you need a reason to say no - then you don't. Reduce pressure on yourself by making a habit of saying no to:
OTHER PEOPLE'S PRIORITIES unless they happen to be yours as well, or you have completed your own 'to do' list.
BLIND RISKS with less than a 50% chance of success. Keep your anxiety levels under control by having a contingency plan as well as an action plan.
BORING WORK. Enthusiasm is a great antidote to stress.
SELLING OUT. Betraying your values damages self-respect, which is an essential element of good psychological health.
EMOTIONAL BLACKMAILERS. Habitually rescuing people from their self-made problems helps no one in the long term and increases stress all round.
BULLIES who threaten with their power and size. Harbouring resentment harbours tension.