Another reason why you should not obsess over negative events and stay neutral is because all that you think in the present moments and past thoughts reflects on future events. So not mastering control of your present moments destroys your present moments that will be coming in the future too.
Suppose you are glum and respond poorly to the present, you are planting seeds of misery for the future. If your beloved someone hurts you and your present moment is in a negative state, you will react with hurt and negativity to anything that happens in the future as well. You will frown at the coffee shop attendant who messed up your order and ruin his day as well. He may, upon your next visit, react to you also in a negative manner and create further suffering for you. Your family will get the brunt of you negative state of mind as well.
Remember always that the seeds you plant, you will harvest in the future, always.