Some of us have known our spouses for ten years, needing more evidence. Some of us have visa offices with higher rejection rates than others, needing more evidence. There are several different reasons. Then there are some of us who just have all the stuff to send, so we do. The IO will take what he/she needs from the application and disregard the rest. Each case is different because my story is not your story for example. None of us share the same story or background or marriage, etc. Therefore each of our applications will look different.