Happiness. Sorrow. Sympathy. Anger. Forgiveness. Resentment. Human emotions were a most complex system, one that was by default set on the mark 'a little bit of misery'. Pinocchio wanted to become a real boy, but he already was one, in a sense.
Na-bots followed every Eve's command and were curious to see the result of her work. They had no idea, not even a concept of how they might feel afterwards. If they had a concept of misery, it wasn't one Eve understood.
With Victor's help and theoretical knowledge, Eve created a prototype of the scheme that should give emotions to AIs in na-bots. She didn't plan to use it on all of them, though, until she was sure that it worked properly. Eve knew there was still a lot to adjust, and there was no way to test everything without some practical tests.
Makes me wonder what if androids in Detroit: Become Human looked like half a meter tall robo-rabbits? Would've been funny, at least.