Title says it all really. It all started when DD3 and DS1 had to sit next to each other on the settee as there was no other spare seats. They began fighting so eventually were sent to their rooms. While I was dealing with this DD2 decided to have a go at them and swear at DD3. Then the fun really began. DD2 was sent to the dining room as she shares a room with DD3. This resulted in DD2 who is 12 throwing the worlds biggest tantrum. She shouted and screamed and sounded like the child out of the exorcist. This lasted on and off for over an hour! She is 12! All is quiet now but I feel exhausted from dealing it. We go weeks where everything is fine and then we'll have one of DD2's tantrum's over something so small. All the arguing between the children in our house really gets me down at times!
I think that sometimes it is just done for your benefit. If you are on your own with them I would just go on strike- go to your room with a book and tell them you will come out when they have finished.