Like you said, explaining a subjective emotional state is hard. So instead, I'm going to tell you a story about a seasick octopus.

So there was this octopus who was seasick. Because she lived in the sea, she was sick all the time. She didn't know she was seasick, because she was born in the sea and had never lived anywhere else. She was miserable all the time, but she just assumed that's how life is; that all the other octopuses must feel the same thing, and she was just terrible at dealing with it.

The one day, the tide washed her up into a shallow pool by the shore, where for the first time in her life she was mostly out of the water. Suddenly, she didn't feel sick anymore; in fact, she felt great! It didn't last, of course, because eventually the tide came in and washed her back out to sea, where she was sick again.

This time, however, she couldn't go back to living the way she had before. Now, she knew what it was like to not be sick. What before she had experienced merely as the absence of happiness had become the presence of misery. She grew desperate to escape the sea again. She started to neglect her friends and family, and every other part of her life. She started taking crazy risks, hanging out in places where the tide might was her onto the shore again, even though there were sharks in the shallow water. Maybe deep down, she figured if she got eaten by a shark or stranded on land, at least she wouldn't feel sick all the time anymore.

She got lucky, and she didn't get eaten. Eventually, she found a coral reef in shallow water, where the ocean was mostly still. It wasn't perfect, and she never got out of the water entirely, but it was still pretty good anyway.