It's rude to befriend someone in order to use them.
Jenny notices there is a new student named Anna in her class.
Jenny wants to become her friend.
Jenny makes friends with Anna so that they can have good conversations and help each other out.
Jenny makes friends with Anna just so that she can ride in Anna's nice car.
Anna enjoys being friends with Jenny and feels welcome in her new town.
Anna finds out Jenny is only using her for her car, and this makes her sad.