Seneca, Letters to Lucilius
104.7-8 (tr. Richard M. Gummere):
Socrates is reported to have replied, when a certain person complained of having received no benefit from his travels: "It serves you right! You travelled in your own company!" O what a blessing it would be for some men to wander away from themselves! As it is, they cause themselves vexation, worry, demoralization, and fear! What profit is there in crossing the sea and in going from one city to another? If you would escape your troubles, you need not another place but another personality. Perhaps you have reached Athens, or perhaps Rhodes; choose any state you fancy, how does it matter what its character may be? You will be bringing to it your own.
Nam Socraten querenti cuidam quod nihil sibi peregrinationes profuissent respondisse ferunt, "non inmerito hoc tibi evenit; tecum enim peregrinabaris." O quam bene cum quibusdam ageretur, si a se aberrarent! Nunc premunt se ipsi, sollicitant, corrumpunt, territant. Quid prodest mare traicere et urbes mutare? si vis ista quibus urgueris effugere, non aliubi sis oportet sed alius. Puta venisse te Athenas, puta Rhodon; elige arbitrio tuo civitatem: quid ad rem pertinet quos illa mores habeat? tuos adferes.