I haven't personally witnessed any race relation issues in town - but I'm a white guy in the exurbs... Someone with a different skin tone might have a different perspective.
Years ago, Anna built a reputation for being unfriendly to people whose necks aren't red, but you'll find that today an overwhelming percentage of our population consists of people who moved here from a closer suburb of Dallas within the last 5 or 6 years.
I'm not saying that Anna doesn't have the occasional redneck racist piece of shit, but I'd wager that that segment of the population isn't significantly larger than the corresponding asshole population in Plano, Allen, or McKinney.
The street that I live on has white couples, black couples, mixed couples, and even someone from Nevada. Our kids all play together and we hang out in the driveway, drink beer, and complain about the people who really deserve our wrath: People who drive too fast down residential roads.