She had had enough; I could tell by the look on her face that this wasn't going to end well. Taking the book from the counter, she screamed at her caregiver, "Well then I don't want to check out ANY BOOK AT ALL!" Child and parent then proceeded to chase each other through the children's department, and neither of them left happy.
I have seen many an angry or upset patron, both children and adults. There are times when crisis can be averted, but much of the time it's simply a matter of waiting it out. In the case above, the child wanted to check out a "fun" book in addition to her required book, and there was a miscommunication about when she would be allowed to do that. Had the child been mostly calm when she was at my desk, I would have said something like, "Well, next time you come in you can get that other book. I can't wait to find out what you think of this one!" Sometimes a calm, happy voice can solve all the problems.
There are other times when a person is fed up and simply needs someone to listen. This might be due to things that have happened at the library or could also be simply because they have had a bad day, and the fine they're trying to pay or book they want to renew is the last straw in a line of bad things that have happened. In that case, I allow the patron to rant, as long as they keep it civil. They are allowed to be upset. They are allowed to think I have made a mistake or that the library's policy is stupid or that our collection is horrible, etc. etc. When this happens I make sure to keep breathing and remind myself to stay calm. The person who is upset is most likely not upset at ME, but rather at the situation they are dealing with.
In the children's department, though, the most common angry patron is someone under the age of five. Young children can become frustrated when they can't communicate their needs or cannot do a thing they want to do. Sometimes this leads to a temper tantrum. If I can talk to them before they reach that stage, I often try to identify what's happening: "Wow, it looks like you're really frustrated because the scissors aren't cutting the paper the way you want." "Oh, it seems like you are really sad because Dad said it's time to leave the library and you want to play with the trains." Oftentimes just acknowledging that the child has feelings and is having a rough time helps.
Depending on the way the child responds to my statement, I might follow up with options: "Would you like a new piece of paper or would you like some tape to fix that one?" "Since you're going home now, would you like me to take a picture of you with your favorite train or would you like a sticker to take with you?" Options are great things. Given options, kids maintain some control over the situation and can often become calm.
If a child does begin a tantrum, other than making sure they are safe and are not harming themselves or anyone else, I generally stay out of the way. Children who have tantrums are almost always accompanied by a caregiver, and unless the caregiver has asked for my assistance, I will leave them to parent their child as they see fit. The same goes for arguments. In the opening example, the parent had already said the child could not take a second book, so I did not offer to check out both or suggest that Mom hold on to the "fun" book until her daughter finished the required reading.
When you encounter angry children in your library, how do you handle it?