Yeah exactly. If anything, I would like to avoid emotions in AI, since emotions makes for an unpredictable outcome. That is the last thing you want in an AI, imho.
Emotions are orthogonal to rationality, that's why you can devise rational plans to minimize or maximize your likelihood of feeling an emotion. In other words it's perfectly rational to act in such a way to prevent sadness or pain, if that's the value you want to optimize for.
You can imagine a creature (natural or artificial it doesn't matter) that feels emotions and nevertheless it doesn't start acting irrationally just whenever the emotion is strong enough.
I could argue that human beings are in many cases such creatures; even apparently irrational behaviour caused by emotional response usually is not a bad strategy in the original environment where that instinctive reaction was selected for.
I'm not sure it would be a good idea to create AI that simulate humans in all aspects, including unpredictability, just for the sake of it. But I understand some might be tempted to explore that area in order to research creativity, assuming it had something to do with unpredictability.
Perhaps we are just fooling ourselves into thinking that our very failures are what enables us to be so $special (put whatever aspect you prefer in $special). Unfortunately we don't have much means to compare us with something else.
EDIT: This fact has been used to argue against the 'enlightenment' era approach to solving problems. Unfortunately I am unable to find the relavant talk on youtube right now, since all the results for 'enlightenment' return mystic sadhu bs.
Consider the ultimatum game[0]. "The ultimatum game is a game often played in economic experiments in which two players interact to decide how to divide a sum of money that is given to them. The first player proposes how to divide the sum between the two players, and the second player can either accept or reject this proposal. If the second player rejects, neither player receives anything. If the second player accepts, the money is split according to the proposal. The game is played only once so that reciprocation is not an issue."
If you are rational and the other player offers you a cent, you will accept. But humans will become disgusted and angry and therefore refuse. A rational counterparty is hence forced offer more.
http://www.psmag.com/magazines/magazine-feature-story-magazi...
Emotions are not really unpredictable, just very limited in comparison to rationality. They essentially can't deal with unexpected or unprogrammed situations.