, you don't work on a day-to-day basis with a data-base of nearly 2 million different people who must be identified by name because (for reasons of privacy) this particular data-base does not contain people's Social Security numbers. :)
I'm talking about a county-wide Library System data-base, where at least a middle initial in addition to first and last name is essential for purposes of identification when registering new patrons for library cards. (I know you're probably thinking: "Well, can't you tell who's who from their address?" Not so! New patrons automatically become "new" when they move from one library district to another, even within the same county -- and it sure helps to be able to distinguish between Maria
C. Velasquez from another library and Maria
R. Velasques who's just come to sign up at your library.
So, you see, some of us appreciate those middle names. :)