Most people don't lose the light in their eyes in one day. It's more of a death by small disappointments. Little by little, life leaks out in a drip, drip, drip of unnoticed little things. It's a huge void by the time it's noticed.
Here's How To Stop It
Do something that makes you smile in every day. Don't let life become about getting through the list of things to do. That's not living. That's existing.
Hold yourself accountable. There is nothing like journaling for feeling your feelings, creating awareness of your situation, and allowing yourself to dream.
Deal with conflict. Lots of small disappointments come from swallowing conflict because we don't want to make a big deal out of a small thing. Small things can choke us if left unchecked.
Go for it. You may lose. Maybe a lot, but one thing you won't have is a pile of regret at the end of your life.
Life is going to bring disappointment. It's unavoidable.
What we can all avoid is allowing those disappointments to pile up and defeat us. When we process things and learn from them, everything becomes a blessing that can help to propel us forward.
If you need inspiration, look to the sun. Some days the clouds roll in and block him from view. Some days it's the rain. Still he persists and keeps on trying. We can keep shining, too!