While working with sentiment and I found out that the reasons for some lexemes to be considered positive could be widely different. E.g.
- happiness is a strong emotion;
- insurance is a useful tool.
But it seems that there are more reasons others than emotion and usefulness to consider a lexeme as positive (unique, irresistible, keen mind, ecosystem, patriotism, softness, etc).
I am looking for some research and/or papers to widen my knowledge of the topic and answer the question stated.