Did I do more harm than good?
... I realize that I imposed my will...


No you did not. The spirit (in an abstract sense!) brought you and the butterfly together. You played your role, butterfly played its.

Was your intent pure? Have you felt the sacredness of the moment? Were you acting foolishly or have your weighted the possibilities?

Life and death is around us and inside us all the time. The fact that butterfly was on your right is a good sign. Life gives us chances once in a while, sometimes it's a chance to change someone's life - and sometimes it's a chance to have someone change our life, to be in the role of the butterfly.

At the end of the day we are not Gods - we can't foresee all repercussions of our acts, even such simple ones as yours. But we can do our best, and if we do it consistently then in the long run we will all be in the best place we could have possibly been.