fachsimpeln — to talk shop. Duden: to talk at length about purely professional matters. Its example is wir haben die ganze Nacht gefachsimpelt, we talked shop all night.
Mahlzeit! — mealtime! Duden: a greeting at midday, especially between colleagues.
ein sehr sachlicher Mensch — a very matter-of-fact person. Duden’s example of sachlich, determined only by the matter itself, not by feelings or prejudices.