To be able to put other people's needs in front of your own is a very important quality. If u want to be a leader u need to do everything in your power to help out the people that are involved with what you are doing. That way the people with you will listen to what you are trying to say.
Being able to say what is on your mind is also another aspect that you need to have in order to be a successful leader. You need this quality because if you can not say what is on your mind, than how do you expect to ever get people to listen to you.
Also, being an all around nice and kind person is an extremely good attribute to have as a leader. If you are not a nice person you will never be able to get people to follow things that you say. Such as if someone was mean n disrespectful to you, you wouldn't want to listen to them n follow what they are doing.
Without the ability to put other people's needs in front of your own, being able to say what is on you mind, and being an all around kinds person I do not believe that you would be able to become a good leader.