I remember that I applied to 14 graduate schools, which is not a so-called crazy number hopefully. However, I do know some of my friends who applied for a bunch of schools, hoping that the chance of getting admitted could be increased to some extent. For example, one of my friends, Arya, she applied for 29 U.S. graduate schools! To me, it was indeed a brave action. Not to mention the expensive application fee, it was very time consuming to tailor the application documents according to different schools’ requirements. In my opinion, it might be more effective using the time for more meaningful and helpful extracurricular activities, internship opportunities or taking more courses.
According to some statistics conducted by a Chinese education organization, it is estimated that, generally, one will receive 10% - 20% admissions of the total number of applications. Since one can only say yes to one university, it means that 5-10 applications are enough. Accounting for some uncertain factors, 10 - 15 applications might be an optimal number of applications. Judging from this, it appears that the number of my applications was pretty reasonable. As a matter of fact, most of my friends applied to 9 - 17 universities.
Just a reminder for the new applicants, carefully choosing universities that you are interested and diving down to see what they are look for are much meaningful than counting on pure chance by applying to a larger amount of universities with low quality.