When I joined BOAC as a young Second Officer in 1970 I recall setting off westbound across the Pond to JFK. There was another aircraft below us which we were slowly overtaking. The Captain told me that if you are overtaking another a/c (which the passengers can see) then you always tell them. On the other hand if you were being overtaken you never said anything to the passengers!
Then there was the classic story of the flight going LHR-LAX non stop, flight time ten hours. Not a word from the flight deck until 5 hours after take off when a click was heard on the PA followed by "HALFWAY". Then a further 5 hours elapsed with no further PAs from the flightdeck!