I want to get better at web development. I can use jQuery fine, I can get relatively complex client side interactions working. I know the basics of catching an error in jQuery and setting status codes in my request coming back from the server.
Also, slightly different, when to use proper requests and how to make secure requests (say the app is encrypting everything going up). As well as learning about the internals of requests going back and forth, so I can develop a deep understanding of what is happening as the client talks to the server.