A short letter to a distant friend is, in my opinion, an insult like that of a slight bow or cursory salutation -- a proof of unwillingness to do much, even where there is a necessity of doing something.
Source: Letter, 10 June 1761 (published in James Boswell, Life of Samuel Johnson, 1791).
-- Samuel Johnson, (Sep 18 1709-1784), English lexicographer, critic; He was remembered for writing the first critique of Shakespeare, 1765 and Dictionary of the English Language, 1755.