It is important that you deal with those who work for you in manner that dose not offend them. The cardinal sin is to cause someone to lose face. There is no graver social faux pas. If a clerk forgets to give you an important message, you should accept the apology and suggest that in future a note should be put on your desk. The domestic helper who drops a crystal glass or plugs the 110-volt vacuum cleaner into the 220-volt outlet will be upset and apologetic. If you shout in these situations, your staff will lose face, your relationship will be spoiled, and their attitude to work may well deteriorate. Also, you should never call or refer to anyone as “stupid.” It is considered to be extremely insulting.