Below about 10,000 feet, US airline pilots must keep the cockpit “sterile”: no chatting or tasks not needed for flying. Even meals must wait.
That's the part of a flight around takeoff and landing. The rule dates from 1981, after crashes caused by distracted crews.
In 1974, an Eastern Air Lines crew chatted while approaching a runway in thick fog. They lost track of their height and crashed miles short of it.