My first "by the way" was at school "you've don't quite well at Maths" that was in the old GCE Pass/Fail days "you got 98% in one 97% in the other"
Or at Nav School, "Do you mind if we knock a couple of marks off so Sgt C, who is going for a commission . . ."
Or "I see you got a Good Show in the Command FS magazine" First I had heard of it. It now has pride of place in the smallest room downstairs.
But I did have very nice letters from two 3*