Yeah. Cultural problems are a tricky one. It's repeatedly shown you can get 15 IQ points from non-genetic differences. So you do need to pay attention to the apparently stupid or shiftless kids so they can in fact be at least some of all they can be. But not neglect the bright ones.

I'll note here as well: it's bloody hard work being a teacher.

(Having met the kids in my daughter's class, her teachers deserve a medal. And they're pretty nice kids.)