If you're dealing with customers face to face, always, and I mean always, greet them with a warm smile! It really affects the customer's mood and it can brighten up a conversation which perhaps wasn't going to be a very bright one... and most importantly it's a Sunnah! Alhamdulillah ⭐ Abu Dharr narrated that the Messenger of Allah said : "Your smiling in the face of your brother is charity." Jami at-Tirmidhi Vol. 4, Book 1, Hadith 1956