Sri Sri Ravi Shankar: No, one does not have to make any effort to develop good qualities at all. Good qualities blossom in you by themselves.
Just like how a bud blossoms into a flower on its own, in the same way good qualities blossom in you naturally. All that you have to do is take the lid off.

See, if you place a lid over a bud, how will it blossom? You need to take the lid off and then it will blossom. It is the same with good qualities.
Only through efforts good qualities will not blossom within us. It is through deep rest, i.e., meditation that it happens.
When you are stress-free, relaxed and are reposing in your Self then good qualities simply blossom from within you.