I call it the Listerine theory of education, based on a famous ad campaign that sought to sell this particular brand of mouthwash on the theory that if it tasted vile, it obviously had to work well. The converse proposition, that anything appealing is likely to be ineffective, is not limited to the realm of schooling. Just as efforts to undermine public education (masquerading as a solemn commitment to leave no child behind) are part of a larger campaign to privatize democratic public institutions, so does an attack on suspiciously enjoyable classroom practices reflect a deeper and wider sensibility. "Feel-good" is an all-purpose epithet, standing ready to disparage almost anything that is too pleasurable.
Source: here