Big hulking dads with do-rags and tons of ear piercings who wear their sunglasses in the library reading picture books aloud to their kids and reminding them to use their "library voice."
Anyone showing anyone else how to use the 'card catalog.'
"You would not believe how long I have been looking for this book! Thank you so much!"
Correctly inferring the title of the book a mumbling kid is describing to me.
"I just wanted to tell you that I loved the book you recommended to me last week."
A security guard showing someone how to use the catalog or how to log on to the computer.
Someone with a Spanish-sounding accent having trouble asking me a question and being able to say, "Hablo un poco español,
si es más fácil."
The expression on a patron's face when she is introduced to interlibrary loan for the first time.
"Oh wow, this library has everything!"
People asking "How much does it cost to borrow a book/DVD from the library?" and getting to reply, "It's free!"