Public vs Private (vs Protected)

Alright /prog/, do you prefer to default your class' members to public or private and why?

class dude : person {
public:
　　int var1, var2;
};

or

class dude : person {
　　int var1, var2;
};

>>11

The idea is to retain control over your classes. Consider the default to be private and you need a reason to go to higher availability. While using interfaces prevents users from using your implementation, it doesn't help if someone inherits your class.