“Blues is easy to play, but hard to feel.”

Blue Monday (1954); the lyrics to the song are by Dave Bartholomew, with Domino later credited as co-writer for his musical revisions to the song in 1956.
Misattributed

[http://www.jfklibrary.org/Research/Research-Aids/Ready-Reference/JFK-Quotations.aspx Response to letter sent by Miss Theodate Johnson, Publisher of Musical America to the two presidential candidates requesting their views on music in relation to the Federal Government and domestic world affairs (13 September 1960); published in Musical America (October 1960), p. 11; later inscribed on the John F. Kennedy Center for the Performing Arts, Washington, D.C.
1960
Context: There is a connection, hard to explain logically but easy to feel, between achievement in public life and progress in the arts. The age of Pericles was also the age of Phidias. The age of Lorenzo de Medici was also the age of Leonardo da Vinci. The age of Elizabeth was also the age of Shakespeare. And the New Frontier for which I campaign in public life, can also be a New Frontier for American art.

Ron English's Fauxlosophy (2016)

[McMenamin, Dave, Lakers want to end series Tuesday, May 9, 2012, ESPNLosAngeles.com, http://espn.go.com/los-angeles/nba/story/_/id/7902623/2012-nba-playoffs-los-angeles-lakers-seek-early-close-series-denver-nuggets, http://www.webcitation.org/67cbXo08T, May 12, 2012]
Bynum in the 2012 NBA Playoffs saying the next game should be easy with the Lakers leading the series 3–1 against the Denver Nuggets and needing one more victory to advance to the next round. The Lakers eventually won 4–3.

Source: Neveryóna (1983), Chapter 9, “Of Night, Noon, Time, and Transition” (p. 238)

"Me and Bobby McGee" another of her greatest hits, the song was actually written by Kris Kristofferson, and first released as sung by Roger Miller
Misattributed

"It Don't Come Easy" (co-written by George Harrison)

Source: Advice to Young Musicians