One of the biggest challenges to being a leader is dealing with disappointment. We can set SMART goals, we can plan, we can carry the plan out, and we still miss the mark. [youtube d2Go9-0HKZY]
Disappointment is as much to leadership as success is so how you handle it speaks volumes to your team. Plus, the day you might be disappointed in one of them they will recall how they've seen you deal with other disappointments.
It's important to recognize the difference between failure and disappointment. Failure is when disappointment wins and you stop trying. A lack of results is more like adjusting the focus on binoculars, when things don't work it can bring us clarity instead of defeat. That path to the goal was hazy, now it's a little more clear. When things don't work it's time to head a new direction. Don't measure success in the win/loss column instead measure by movement. Disappointing results are frustrating, yes, but they also give a clear indication that it's time to chose a new direction.
Disappointment is perfectly okay but let it help you focus instead of letting it make you quit.