Macedonia vs. Athens
It's true that Aristotle was not born in Macedonia, but his hometown was taken over by Macedonia fairly early in his life. Plus, he had long-standing familial ties to the Court of Macedonia and was friends with the king, Philip. So he was pretty much a Macedonian man.
Unfortunately, that's not such a good thing when you're living in Athens, as Aristotle was during his 20 years of study at Plato's Academy. The problem was that Macedonia was just a tad warlike and the noble citizens of Athens viewed the state (and its sympathizers) as a big threat, especially during the reign of Philip II. So after Plato's death in 347 BCE, the political tension was just too much for poor sensitive Aristotle. He fled and headed for Assos.
Aristotle stayed away from Athens for about 10 years. But things calmed down politically, and the lure of big city was too much for the man—so he returned. He had a good run this time…10+ years of more or less smooth sailing. But then politics once more interceded.
In 323 BCE, Alexander the Great, who had been the king of Macedonia, died. Athens was now definitely not safe for a Macedonian man, especially one who had associated with Alexander. Aristotle was on the verge of being charged for impiety (like Socrates!). So he declared, "I will not allow the Athenians to sin twice against philosophy"—and he fled back home.
Poor Aristotle. All that political intrigue must have been too much for him, as he died less than a year later.