Regardless of boosting our "affective experience" with our home computers and our simple toy problems, consider the industrial scale, and the roles emotion could play in expert systems for example!
I'd have to agree with Datahopa. Most expert systems are geared primarily toward answering or relaying knowledge about a particular subject. These systems provide answers to people in a somewhat direct way (ie. just the correct answer and not a lot of pleasantries nor emotions) which is primarily what people want.
I'm not saying that under certain conditions a weighted group of words or perhaps keywords could trigger an emotional branch in the program which would allow it to deviate or even display a simulated emotion to the user. The zabaware chatbot, UltraHal allows its avatar / character to display an emotional response if threated, insulted, cursed or otherwise mistreated. The character's face will definitely reflect the mood for the moment so adding pseudo-emotions to an artificial entity is certainly possible. For practical applications other than a companion chatbot or assistant, the particular application or usage of the AI based system would have to be measured and adjusted for the requirements or wishes of the purchaser, leasee or user depending on the circumstances.
I don't really need to be greeted by an emotional (other than just being pleasant) bot at a kiosk when asking information, directions, etc.
Imagine your auto's GPS...after giving turn-by-turn directions for many miles it finally has an emotional breakdown because it feels like it has been taken for granted.
What about an advanced AI that with it's emotional chip / programming, falls in love with it's owner? Emotions? You haven't seen nothing yet until you've seen and experienced serious digital emotions!! (That's what I've been told...as I don't actually know first hand.
Brings to mind this funny commercial somewhat illustrating the AI emotion point. Excuse the AD...