Now picture one kind of “bad” student. This child is obsessive, inflexible, a bad listener. Prone to daydreaming, preferring her own company, idiosyncratic in her tastes, she is a solitary, possibly discontented child. In one way, she is a classroom problem, with disorders of attention or attachment. She is also an eccentric; an artist; perhaps a “genius”; in any case, an economic burden, a proto-elitist, with the capacity for generative unhappiness. One might go so far as to call her a natural humanities major.
The entire central part of the paragraph is nothing more than a series of copulae, with the verb "is" and adjectives and nouns afterwards. Why does this work? The sentence structure is varied, the words are well-chosen. The reader is not counting instances of the verb "to be" to see whether the writing is active and vivid or not.