Nothing is so easy but it is difficult when you do it reluctantly.
Terence (186?-159 BC) African-Roman dramatist [Publius Terentius Afer]
Heuton timoroumenos [The Self-Tormentor], l. 806 [tr. J. Sergeaunt (1912)]
Alt trans: "There is nothing so easy but that it becomes difficult when you do it reluctantly."