Most libraries put notes on patron records for a variety of different reasons. When you check out your books, the person behind the desk can usually see if you have some books being held behind the counter for you, if you have fines, if you have tried to convince us that you have returned 16 of our books that somehow miraculously are not on our shelves and are still checked out to you even though you turned them in, if you are allowed to check out extra books because you are a homeschooler, if your spouse is authorized to use your card, etc.
Most of these notes are, obviously, administrative in nature. The appropriate library protocol is to end the note with the date it is entered and your initials, so if someone later has a question about the note, they know who to talk to.
Someone at my new library, however, has a more colorful sense of humor. On the accounts of a select number of our regular patrons, they have written notes. Some of them are informative ("Will talk your ear off if you let him"). Some of them are endearing ("Sweetheart!"). My anonymous colleague does not put their initials or a date by these notes. I wish he/she did, because today I saw one that took the prize both for accuracy and for its ability to make me feel better.
I dealt with a particularly trying gentleman for nearly 10 minutes, arguing about due dates, renewal policies and why we don't allow cell phones in the library. He was quite sure that I was the stupidest human being ever to walk the face of the planet, and that he knew much more about libraries ("I've been coming to this library longer than you've been alive!" - which made me think: Why, yes, you have, and I've been working here two months and I know the policies better than you! How'd'ya like them apples?) I scanned his card and discovered this succinct, to the point note on his account:
I couldn't help it, I chuckled a little. Luckily, he didn't ask what I thought was funny.