What items do other people keep in their car ‘just-in-case’; to be prepared for any eventuality?

I have recently got my first car and I would like people to contribute helpful suggestions for useful things I should keep in it. Not just for mechanical problems with the car, but anything. Currently, I have the tool kit for changing the tyre, paper serviettes, tissues, drinking straws, a plastic bag to put rubbish in, a sterile triangular bandage, an abridged first aid book, the car’s service record book and an unopened bag of rice cakes. What do others keep in their cars?