I agree with your wife that kids need to know when you are displeased. I agree with you that anger isn't the only way to convey this and that anger has unfortunate negative consequences. People who use anger to get their point across usually haven't found another effective way of communicating their point. Has your wife read my book "Raise Your Kids without Raising Your Voice?" It has lots of ideas on how to gain cooperation without using anger. Your wife is using a risky technique - one that tends to work in the short run but that can cause serious problems in the long run. I don't think it's worth taking this chance.
Sarah Chana