In Anime...

I think I know what is behind all the shows with Super Sayajin style fights. It's peoples desire to unleash all their rage upon an enemy. The punishment the heros take and endure is like all the pain they feel they have aquired over the years, and the final assault/big climax, is the final release of all that pain and anger upon it's source. It's the solution they dream of, being able to send all their pain back to the source, and never deal with it again. If only life's real problems were so simple.