Great post. I think there may be something to be said about a connection between clinging and the concept of 'transparency' in philosophy of mind - which refers to the property certain qualia has of not being experienced as a representation, but as reality itself, or some other less definable thing. It seems to me that states of clinging involve significant transparency, in that I am not interpreting my emotions as emotions, but am instead helplessly persuaded by or convinced of them in some peculiar way that makes them go, in some sense, unnoticed. You mention that you don't think depression is very clingy - in my experience it isn't very transparent. Depression can feel like a cluster of sensations that are being imposed on you against your will. Although this may characterise states of intense clinging (like an angry outburst) I think its only upon reflection that they feel that way. In the moment the anger is wholly persuasive, it is the core of your being. Depression, on the other hand, can be noticed as a presence in real time.