Hissy fit

Barely a question, but could it be that "hissy" is simply the Norwegian word meaning "hot-tempered" - spelt hissig but pronounced hissy?

Most of the dictionaries agree that it may be related to hysteria. The English word hiss which is imitative in origin (hissing things make a hissing sound) could be an influence or reinforcement. Also, it seems to be Southern in origin and the Norwegian immigrants tended to concentrate farther north. If the phrase were coming from Minnesota, Iowa, etc., it could be a factor in favor of a Norwegian influence.