Καφετζής is the owner of a traditional coffee house and someone who prepares coffees for customers. Καφετζού, on the other hand, is, more commonly, the fortune teller who reads the dregs in the coffee cups (the dregs, not the grains).
It was definitely Ν' αγιάσει το στόμα σου. All the information here is worth remembering. I liked nickel's 'γεια στο πληκτρολόγιό σου'. A touch of good humour as well. My Easter is nearly complete.