A boss manages tasks, whereas a leader encourages and empowers people, setting the pace and the example.
A leader motivates you to fly and soar high whereas a boss demands adherence to rules and regulations because flying disturbs the status quo.
The difference is a leader shows an example. Boss orders and demands. The leader is successful and lovable; boss got the failure and disliked.
A leader is visionary who is able to give a direction to people and help them along the path of fulfilling that vision, also motivates people under him/her; A boss is a function of positioning and hierarchy, directs the team based on KPIs within an organization.
An authentic leader's job is not to look inward to the organization, it is to look outward and forward - watching the environment for emerging problems and addressing them, modifying the strategic direction when necessary, and acting as an enabler to let the executors of the strategy do what they do best.
An organization with good informal leaders can survive poor leadership at the top; indeed, the best organizations have leaders at all levels. And many times, good leadership at the top is not being intimately involved in change; rather, it is setting out a future direction and then staying out of the way. It is the informal leaders who really get things done. Leaders are influencers, and bosses are controllers.