Autonomy - Behavior that is self-enforced or self-initiated. Autonomy provides for a sense of freedom in how you live your life, allowing you to get excited about your own choices.
Competence - Feeling effective in your environment. A sense of competence helps people feel like they play a role in solving their own problem.
Relatedness - Feeling cared for and connected with others; sense of belonging. Humans are social creatures and have a powerful need to be connected and recognized by others. This applies to social networks for example.