getting the job done using authority is easy when compared to building a happy team, do you agree?

I would disagree. I believe in sourcing a team of skilled individuals, train them, give them the freedom and make them acoountable for their actions. Motivate them. Reward good work in public and give feedback on areas of improvement in private. 

"Want to do"  yields better results than "have to do "

 

Yes, I agree because of the following two key reasons:1) As authority is a fomally granted power with the reght of providing commands to subordinates, it can helps in getting the job done for a short time.
However, it may not assure long-lasting positive effects.2) Building a happy team or developing an effective team needs time to pass through the basic tages of team developement, therefore, it requires leadership competencies (knowledge & skils) to do so.