Cicero, Paradoxa Stoicorum 5

Men seek retreats for themselves, houses in the country, sea-shores, and mountains... But this is altogether a mark of the most common sort of men, for it is in thy power whenever thou shalt choose to retire into thyself.

Take away thy opinion, and then there is taken away the complaint, 'I have been harmed.' Take away the complaint, and the harm is taken away.

At dawn, when you have trouble getting out of bed, tell yourself: 'I have to go to work — as a human being.'