In the Exodus story, the Israelites were led away from Egypt and into the wilderness. They often grumbled and complained. As they were on the move they had to learn to live without jobs, without homes, without a way to find food (except for what God provided for them by way of the quail and manna) and without knowing where they would wind up. But there was one thing they couldn't do without... leadership. As Moses was up on the mountain meeting with God the people fell apart. Think about it, they could live without all the aforementioned things but they couldn't live without leadership.
In every leadership situation I've ever been in... as a pastor, coach, band leader, manager, anything... there have been dissenters. I used to think that I was the common denominator. Since all the people kept coming to me I assumed I was at the heart of the problems. While I'm sure my inability to lead has created issues from time to time, what I've learned is criticism goes with the territory. If you lead people, someone will grumble. Period. A part of the reason why leadership exists is to absorb the complaining. As a leader, your job is to recycle the negative into something positive. What can't be recycled needs to be discarded. Grumbling is not necessarily evidence that you're doing a poor job of leadership. Grumbling is evidence that God has placed you in a leadership position and He expects you to deal with it. He knows His people can manage just about anything... as long as they have a leader.