So many footballers have crossed from red to blue, or turned from nerazzuro into rossonero, that you have be a special sort of Ex to become the sustained focus of bile in a modern Milan derby.
Should Ali Sulley Muntari, for instance, make the starting XI tonight for AC Milan, his name may generate a few shrill whistles, some boos from his former fans, but his past as an Inter player, while full of medals, does not define the Ghanaian midfielder.
His transfer, last year, across the city made few headlines. Just being a turncoat does not make you a traitor. Inter Milan and AC Milan are businesses as well as combatants, and their direct-transfer deals are now frequent.
Andrea Pirlo, once marginal at Inter and then masterly at Milan, was a source of embarrassment, more than an invitation to personal scorn, for the Inter who let him go to their oldest enemy, having failed to appreciate his potential.
Ditto Clarence Seedorf, who switched from blue to red.
"Inter fans still loved me even when I came to AC Milan and started winning trophies," Seedorf said. "They understood that I had given my best there."
There lies one explanation of why, tomorrow evening, a distinct and possibly disturbing venom will be directed at Mario Balotelli on his first derby as an AC Milan player. Balotelli did not engineer a transfer from Inter to AC Milan; he had two and half years at Manchester City in between, during which he emerged as a front-line Italy international, among other well-chronicled events. Many at Inter merely shrugged, back then, at the teenager's departure for City, for a substantial profit to Inter, more than €21 million (Dh102.1m) for a footballer who had come up through their youth ranks.
That fee acknowledged a magnificent potential. But its yield in Inter's black-and-blue had been measured out in cameos: a few spectacular goals, like the long-ranger against Rubin Kazan in the Champions League; some match-winning displays, like his two goals against Juventus in the Coppa Italia, and handsome enough statistics for a man then still shy of his 20th birthday - 28 goals in 86 appearances. Set against that, though, is the powerful, residual memory of a young man who always set himself apart.
Balotelli's last sighting in an Inter jersey was a poignant one: an unused substitute in the 2010 Champions League final, the crowning, historic moment and the third part of that year's treble. Jose Mourinho, Inter's coach, had lost patience with Balotelli's indulgent individualism.
At Inter, the team too seldom seemed a priority ahead of the selfish interests of the young man. Balotelli had thrown his Inter jersey to the ground upon being replaced by Mourinho in the Champions League semi-final against Barcelona.
Worse, there was always his known childhood affection for AC Milan. Balotelli had been a Milan fan growing up, adopted by an Italian couple, the son of Ghanaian immigrants. He never hid that, as an Inter employee. He sometimes brazenly advertised those loyalties. He wore an AC Milan jersey on a television show while under contract with Inter. Inter's self-appointed dressing-room shop steward of the time, Marco Materazzi, tells how he once took a pair of scissors to the AC Milan-embroidered socks Balotelli wore to practice.
These provocative gestures, quite a catalogue of them in the storybook of a man so young, are interpreted as an invitation for interisti to now taunt Balotelli. He knows that. How some in the curva nord, the blue cauldron, choose to do so tomorrow will be under scrutiny. Inter have already been fined for the racially abusive chanting of some of their followers against Balotelli at a match, against Chievo, he was nowhere near.
With four goals for Milan in his first three games, Balotelli can count on plenty of backing from the south grandstand at San Siro. He will hear his red devotees jeer Inter's Antonio Cassano, who crossed from red to blue last summer and, being Cassano, made derogatory utterings about AC Milan on his way out. But the biggest noise will be around Balotelli, loathed and disloyal in the eyes of many; to their rivals, a prodigal son come home to save AC Milan's season.
Fixtures
Today
Palermo v Genoa 11.45pm
Tomorrow
Sampdoria v Chievo Verona 3.30pm
Atalanta v AS Roma 6pm
Bologna v Fiorentina 6pm
Cagliari v Torino 6pm
Juventus v Siena 6pm
Parma v Catania 6pm
Inter v AC Milan 11.45pm
Monday
Udinese v Napoli 10pm
Lazio v Pescara midnight
Serie A table
Team P W D L GD P
Juventus 25 17 4 4 32 55 Napoli 25 15 6 4 25 51
Milan 25 13 5 7 13 44 Lazio 25 13 5 7 6 44
Inter 25 13 4 8 7 43 Fiorentina 25 12 6 7 15 42
Catania 25 11 6 8 2 39 Roma 25 11 4 10 2 37
Udinese 25 9 9 7 1 36 Parma 25 8 8 9 -2 32
Torino 25 7 11 7 1 31 Sampdoria 25 8 6 11 1 29
Chievo 25 8 5 12 -14 29 Cagliari 25 7 7 11 -13 28
Atalanta 25 8 5 12 -13 27 Bologna 25 7 5 13 -2 26
Genoa 25 6 7 12 -11 25 Siena 25 7 6 12 -7 21
Pescara 25 6 3 16 -31 21 Palermo 25 3 10 12 -17 19