I was not allowed to take spherical trigonometry because I'd sprained my ankle. Because I'd sprained my ankle, I had an incomplete in gym, phys ed. And the rule was that if you had an incomplete in anything, you were not allowed to take an overload.
My decision to come to Bell Telephone Laboratories immediately after obtaining my Ph.D. in 1936 was strongly influenced by the fact that my supervisor would be C. J. Davisson.