Most interactions with patrons at the desk last less than a minute, two at the most because it takes a long time to print up a due date slip listing all of the 50 items checked out.
I do not know if this is only for specific patrons who are "loose" when it comes to self-disclosure or if the circ desk is the equivalent of a bar. Patrons can be particularly gabby, and I'm not just talking about the lonely elderly ones either (it's worse when they call because I feel bad when I have to politely tell them I have to go back to work after helping them).
Popular topics of discussion are
1. The weather; from a blizzard to a heat wave, patrons will always mention the obvious. Although, I particularly hate it when patrons mention how great it is outdoors and I'm stuck indoors and I also just started my shift -- don't rub it in!
2. Changes in library policy; it's always fun to bond with patrons by complaining about "The Man," you know, the one guy in his executive suite, smoking his cigars in his expensive suit who is always increasing library fines and shortening hours.
3. Personal issues; most of the time I honestly do not need any more information other than your library card number, and sometimes your name or address. Everything volunteered varies so greatly on many levels. It can range from happy subjects like finally getting a job after using the library to find jobs, to the sad like a widow clearing up a recently passed away spouse's account.
No matter what the topic, I openly welcome anything over the awkward silence of waiting for the printer to finish. I love it when patrons get really excited when they see that I am willing to listen. I had an elderly patron go on and on about a play she was putting on and kept inviting me to go. I recently had a patron tell me all about her trip to Greece which occurred during the economic riots; her husband was pick-pocketed within 20 minutes of setting foot on land and she came in to pay for books they lost when they had to quickly leave their hotel due to the riots.
So bring some books and some stories to the check out desk and I'm always willing to lend the books and an ear.