I'm not a big fan of tattoos, but I have to say that I would love to write on my body a sentence from a poem written by the greek Arkilochus (he was born around the 648 a.C). It is one of the most intense, deep, extraordinary poem I've ever read. It's like a warning to me.
This is all the poem in ancient greek:
θυμέ, θύμ᾽ ἀμηχάνοισι κήδεσιν κυκώμενε,
ἄνα δέ, δυσμενέων δ᾽ ἀλέξευ προσβαλὼν ἐναντίον
στέρνον, ἐν δοκοῖσιν ἐχθρῶν πλησίον κατασταθείς
ἀσφαλέως· καὶ μήτε νικῶν ἀμφαδὴν ἀγάλλεο
μηδὲ νικηθεὶς ἐν οἴκωι καταπεσὼν ὀδύρεο.
ἀλλὰ χαρτοῖσίν τε χαῖρε καὶ κακοῖσιν ἀσχάλα
μὴ λίην· γίνωσκε δ᾽ οἷος ῥυσμὸς ἀνθρώπους ἔχει