I didn’t attend the funeral, but I sent a nice letter saying I approved of it.

Mark Twain (1835-1910) American writer [pseud. of Samuel Clemens]
(Misattributed)

This appears to have originally been based on a comment by lawyer and jurist Ebenezer Rockwood Hoar in 1884 regarding the death of abolitionist figure Wendell Phillips. In retelling it has been attributed to (and targeted at) a variety of people. It was not attached to Twain until 1938, and the connection was widely popularized by a reference from columnist Walter Winchell (1946), and by Hal Holbrook's one-man show, Mark Twain Tonight (1954).

For more discussion of this quotation's origins, see Quote Origin: I Did Not Attend the Funeral, But I Sent a Nice Letter Saying I Approved of It – Quote Investigator®.