When we climb a tree, we face many obstacles. Very first time, we will face the bite of ants on first branch. If you sit on that branch, keep looking at the bite places, then you have to fight with some more ants. And at the end, we have to get down.
Journey of our life is similar to climbing the tree and bites of ants are like difficulties/pain times in our life. So if we keep thinking on same matter happened earlier, then we will be caught more by that pain. And our unhappiness will keep growing. We will be broken down instead of growing up. So keep the life simple and truth. Whatever happens, just leave those at that time and just move on. God might be waiting you at the next door to hug you.