Science is inseparable from measurement, and measurement is inseparable from length units. The establishment of basic length units such as kilometer, meter, decimeter and centimeter is completely an artificial agreement. 
the scientific conclusion is completely a subjective agreement, not an objective standard.
Having solid basic dance skills must go through years of unremitting hard training. Dancers performing at the Spring Festival Gala must have solid basic skills. Years of hard training are boring. Therefore, performing at the Spring Festival is boring.