Hospitality runs deep in Egyptian culture, and it's common to be greeted warmly and asked questions out of genuine friendliness — a bit of small talk, even a few words of Arabic like "shukran" (thank you), tends to go a long way.
At religious sites
Dress modestly, especially in rural areas, mosques, and souqs, is official travel-advisory guidance for Egypt — covered shoulders and knees, and removing shoes before entering prayer halls, are the norm, and headscarves are often provided or required for women at specific sites. Your guide will flag exactly what's expected at each stop.
The right hand is traditionally used for eating and greeting, and it's considered polite to accept tea or coffee if offered during a shop visit, even without any obligation to buy anything afterward — see Is Bargaining Expected When Shopping in Egypt? for more on how shop visits typically go.