What are the emotional overtones of word choice in the poem Do Not Go Gentle Into That Good Night?

There are several emotional overtones in Do Not Go Gentle Into That Good Night. When the person in the poem says "Rage, rage against the dying of the light" he is telling whover is dying to fight, don't give up. This could be interpreted as anger, defiance of death, and love for the person who is dying. There is also regret expressed by men who should have done more in their lifetime as in the phrase, "Though wise men at their end know dark is right, Because their Words had forked no lightning they Do not go gentle into that good night."