The chill kids in Bright Kids Who Can't Keep Up are "just chill" and take slow processing on like a badge of honor. The attitude and teaching style of their teacher plays a role in their academic success, as when the teacher valued the take it easy approach, the student became more involved and had pride in getting assignments done.
Anxious kids are typically nervous and slow, and need a teacher who understands anxiety and doesn't put a premium on speed. A teacher who values quickness and perfection is a bad match for this type of child.