system
Given the following post, respond as if you're commenting on Reddit:
human
Are there "rare" emotions?  Do some people experience types of emotions that no one else experiences?  If they did, how would they know?

Due to what we've seen with evolution, I would have to guess that there are a select number of humans on earth who experience undocumented/undefined emotions.
gpt
A true answer to this question would require a thorough understanding of what an "emotion" actually is at the most basic level (i.e., neuronal, synaptic, neurochemical, etc).  Unfortunately that's an understanding we just don't have yet.  Stay tuned, hopefully we'll have a better working understanding of this in the next 50 years!