Trust is a fragile thing for a leader. People can trust leaders one day and completely lose trust the next. Trust is foundational to leadership. Without trust leaders have a difficult time getting people to follow.
Trust is the foundation to every solid and functional team. Without trust team members will hold back thoughts and opinions for fear of conflict with negative consequences, won’t be as committed, won’t ask for help, will misjudge the intentions of teammates and so forth and so on.