title: Why seal a class?
body: <p>I'd like to hear what is the motivation behind the bulk of sealed classes in the .Net framework. What is the benefit of sealing a class? I cannot fathom how not allowing inheritance can be useful and most likely not the only one fighting these classes.</p>
  <p>So, why is the framework designed this way and wouldn't it be unbreaking change to unseal everything? There must be another reason than just being evil?</p>