Have you ever asked yourself: Who decides which exposure is the right one for my picture? If you are in green rectangle mode your camera decides. Sometimes this makes things easier, but even when you switch to P, Av, Tv the camera decides what is good for you.
It takes another small step to get to M. The place where you decide how your picture should look like. I played around and wanted to take a picture with a lot of light (often called high key lighting). The focus could be a little bit better but I like it.