Someone I helped (found him 2 newspaper articles he'd been unsuccessfully searching for on the web) not only told me "You rock, girl!" but then almost wept when he tried to explain how important these articles were to him. His voice shook and his eyes were blinking rapidly so that tears wouldn't form as he expressed his gratitude. Although I couldn't figure out how from their content, the articles are apparently important to a court case the man is involved in.
It's days like this that make me glad I became a librarian, and not a rodent-wrangler for the movies (which was one of my dream careers in college- I could have worked on the "Willard" remake!) or the person you consult about which colors to paint the exterior of your restored Victorian house (who isn't the person who actually does the painting)-- after all, how many rodent wranglers have been honored with an action figure?
He also said "I love you" to me, which was strange, but I will take it as merely a display of thanks and not as a creepy/stalky profession of desire.