The only useful things you can learn in university classes are those that you already know you want. Not because you have to sign up for the classes, but because if you don't want to learn from them you can and will pass them without integrating new knowledge.
To further elaborate the question: What are the most universally and most useful skills one could learn at a university? Currently, I am studying physics as an undergraduate and I am thinking about my career options. I have gotten opinions in other forums as well but I would really like to hear your thoughts and I also think that other LessWrongers would find such a list useful. To give you a rough idea of what I mean I have two examples:
What are some other skills along this line that are universally useful?