In his letter to Minicius Fundanus, Pliny tackles the importance of relaxation and leisure (different from the idea of not doing anything).
It is remarkable how we account, or seem to account, for each individual day in Rome, but not for a number of days combined. If you were to pose to anyone the question, ‘What did you do today?’, the answer would be: ‘I attended an investiture of the adult toga, or I was present at a betrothal or a wedding; one person asked me to witness his will, a second to plead for him in court, a third to act as assessor on the Bench.’ These duties seem necessary on the day you perform them, but once you reflect that you have spent every day doing the same things, they seem pointless, and much more so when you retire from Rome, for it is then that you recollect: ‘How many days I have wasted, on what tedious pursuits!’
This is my own reaction once I am in my residence at Laurentum, reading or writing or just indulging in the physical relaxation on which the mind depends for its support. I hear or say nothing which I regret having heard or spoken; no one in my presence criticizes another with unkind insinuations, and I have no harsh words for anyone––except myself, when my writing falls below standard. No hope, no fear agitates me; no gossip disturbs my mind. Conversation is confined to myself and my books.
What straightforward, unblemished living this is! What delightful and what honourable leisure, nobler than virtually any active occupation! The sea and shore, my true and private maison des Muses, how many thoughts do you inspire, and how many do you dictate!
This is why you too must at the first opportunity abandon this city din, this pointless bustle, these quite foolish toils, devoting yourself to your studies or to leisure, for as our friend Atilius most learnedly and also most wittily remarked, it is better to seek relaxation than to do nothing. Farewell.