Can you expand on that? I think they are almost always grouped as opposites. Sharp and dull, Light and dark, Big and small, Love and hate. You could try for apathy as the opposite of love or of hate, but that is like saying gray is the opposite of white or black - it is just something in the middle.
I've tried to define love and hate in similar terms, minding what I think is their opposite nature. Self sacrifice to help another person is love, self sacrifice to hurt another person is hate. I think it works.
The opposite of love isn't hate. The opposite of love is indifference. Relationships can survive hate and return to love. When they just stop caring, the relationship is over.
Much like depression is not sadness. Sadness is meaningful. Depression is the dullness of absolutely nothing having meaning anymore.
Of course they can be considered opposites, along a certain axis. It all depends what you think is the most relevant axis for comparison.
In this case, I think emotions lead to memory leads to learning. It's more important to care about the instructor and the material than it is to feel positive about it. To purposefully score low, you need to master the material enough to prevent yourself from being right by accident.
They’re feelings, not actions. You can love and hate something and someone at the same time (see Apple and Star Wars fandom), but it’s quite hard to love or hate something and feel apathetic about it at the same time.
big and small are just relative descriptions. Something can be both big and small, consider the moon (big to us, small to the sun), but it is hard to describe somethings size while not thinking/comparing/considering about it.
Light and dark can be considered emotions to. You can harbor light and dark thoughts at the same time on the same subject. Light and dark are still opposites, like big and small. I don't find the argument compelling yet that love and hate are not opposites.
If indifference is the opposite of love, it is also the opposite of hate. That would make love and hate the same or close. I don't buy it. I would consider negative and positive to be opposite, and zero to be niether. Zero is apathy/indifference.
You can’t be big and small to something at the same time the way you can love and hate something at the same time.
Your point about 0 is resonable, but it’s more of a U shape.
Both are intense feelings that will stimulate arousal. In practice, it’s easier to move from love to hate and back to love than it is to move either to apathy — and cycling between them doesn’t involve apathy at all.
And then we have things like disgust, which I would say is more dissimilar to love than hate.
I've tried to define love and hate in similar terms, minding what I think is their opposite nature. Self sacrifice to help another person is love, self sacrifice to hurt another person is hate. I think it works.