Don't quit a job because there are some unpleasant things connected with it, lest you should find others much worse.
Don't give a guarantee that you will not make good, lest you be accused of being dishonest.
Don't claim to furnish more goods for the money than anybody else, lest your customer should find the same value somewhere else.
Don't disagree with your customer if you can help it, lest he should doubt your judgment.
Don't sit out in front of your place of business, lest people think you are doing nothing.