Some businesses close on Saturday or Sunday as well. Shops and Stores are usually open on Friday, closed on Sunday. Do not expect everyone to be punctual.
Private businesses work longer hours.
There is no lunch break at noon. If you are staying in Egypt for a relatively long period, you may need to register your passport at the Police station. Most major hotels will do the registration as a courtesy. Consult your hotel front desk upon arrival. To avoid cultural misunderstanding and prevent any misinterpretation, always greet people with only a handshake, whether you are a man or a woman.