...chatting with patrons leads to impromptu booktalks and the like.
Case in point...
Me: I read lots of picture books.
Little Boy: Why?
Me: Because I'm the children's librarian. I want to know what children like to read/hear so I can plan story time.
Little Boy: Can you do story time now?
Me: [slight pause] Of course.
And I proceed to read him two of the books I was shelving (Good-Night, Owl! by Pat Hutchins and The Giant Hug by Sandra Horning). The little boy was four-years-old. He enjoyed the first book, but lost interest in the second (it was a bit long). I love being a children's librarian. There's no routine, only spontaneity.