There's nothing healthier for body and soul than a new beginning, making a fresh start. The spirit influences the body. So, when the spirit declares a fresh start, the body becomes rejuvenated! By removing the focus from our setbacks and disappointments, we avoid sadness and depression. And if we messed up by committing some transgression, we simply ask forgiveness from Hashem and promise to do our best to improve. Once we've made teshuva, the past is wiped away – the transgression no longer exists! Therefore, by declaring a new start, we destroy sadness and depression, especially the depression that follows a transgression.