A childhood belief about names

When I Was in the thrid grade, There was a girl in my class known as "Sam", which I thought was a peculiar name for a girl, though I soon learned that it was a nkckname for "Samantha", a name I had not previously heard of. Also in my class was a girl named "Pam", whom I'd known since first grade. I decided that, since "Sam" was a nickname for "Samantha" (in the case of the new girl I'd met, at least, and presumably whenever a girl has the name "Sam"), "Pam" must be a nickname for "Pamantha". You should have seen the strange reactions the first time I referred to Pam as "Pamantha"!