It's hard to imagine someone as beloved as Ray Allen was in Boston suddenly becoming a villain.
But leaving the Boston Celtics for their arch-rival, the Miami Heat?
To do so for half the pay?
That'll do it.
Despite being an integral part of the C's return to glory with Banner 17 in 2008, there's little doubt that the future Hall of Famer will be greeted with his share of jeers from Celtics Nation when he returns to the Garden for the first time with his new team on Jan. 27.
Still, does that make Allen the biggest villain on the Celtics' schedule?
Heck, he might not even crack the top-5 even with there now being an opening with Mike Bibby and his turnstile-esque defense no longer in the league.
Celtics Nation serenaded him with boos every time he stepped on the floor following comments he made in 2008 (then with the Atlanta Hawks) about the C's having "fair-weather" fans.
For years, he was a lock to be on the franchise's most hated list.
Chicago's Joakim Noah is another player that Celtics fans have no love for, although most of the dislike for him stems from his not-so-fuzzy relationship with Kevin Garnett.
You can throw LeBron James in there as well.
C's fans have nothing but disdain for James, even more so after he led the Heat this past season to an NBA title which included some monster games in eliminating the C's in the Eastern Conference finals.
Go down the list of the game's elite players and there's a heightened level of dislike for all of them by Celtics fans.
But when it comes to Public Enemy No. 1 around here, there can only be one Kobe Bryant.
No player brings out more vitriol in Celtics fans than Bryant. It's in part because he's such a dynamic player who has been among the game's best for years.
The fact that he plays for the C's longtime rival out West, the Los Angeles Lakers, just adds to the hatred.
More than anything, Bryant does it with an elevated level of cockiness that will never sit right with fans in these parts. Some of his biggest game-winning shots have come at the expense of the Celtics.
Those are the moments that Bryant has made no secret about relishing his role as a basketball assassin, even more so in delivering that killer shot to bury the Green Team.
But if you sift through the mutual hatred for one another, at the core of it all is respect.
Bryant has repeatedly said he loves the rivalry because of the storied tradition of both franchises. And the C's certainly have a great deal of respect for what Bryant has done on the floor in establishing himself as one of the greatest players to ever play in the NBA.
Respect aside, Celtics fans will still boo the heck out of him with the kind of intensity that's fitting of an arch-rival.
And Bryant wouldn't want it any other way.
"The fans hate your guts when youre playing here, but very appreciative of the talent, Bryant told Yahoo! Sports. When you see them out on the streets, its always a warm reception. Man, I hate you, but I love watching you. How do you think the Celtics are going to do? Its a running conversation.