The Wikipedia article at https://en.wikipedia.org/wiki/Qualia is about the subjective experience of one mind which is not knowable as being different from that of another mind. One main problem of Qualia is why we perceive different colors such as RED, amber and GREEN on a traffic stoplight. As philosophers of mind, we may ask ourselves why anything should ever look red or green at all, as if redness and greenness were more spiritual than physical. But when we see a round, bright red light at a traffic stop, our conscious brain is also "tickling" our strongest memories of redness in general, so that we are perceiving redness as a category of color. Since red objects are fewer in number than green objects, red is both a shocking and a beautiful color. Green objects, being more prevalent on Earth, are soothing and tranquil to look at. It is especially important that red is the color of human blood, which may shock us, and of things on fire, which may frighten us. As newborn babies seeing a red toy, we have no associative memories of redness to engender emotional responses, but over time we develop a subjective awareness of red objects and of green objects.

Pain and pleasure may be a contrast between insistent, accelerated sensations in the case of pain and slower sensations yielding to pleasant memories in the case of pleasure.