Instead of only negative effect for stress, add positive effect while exciting

[Tranoze]

So stress bar should change to Emotion bar, at range from -100 to 100. 

While Emotion is larger than 0, morale expectation will increase base on current Emotion(and will balance out at some point), and Dups will gain small bonus speed at working. At early game, Emotion will stay at -20~20, and at later game, when you have good enough environment dups can be happier.

massage wont increase emotion above 0. Only Morale can do that.

While Emotion is lower than 0, it will work as current stress system. Emotion will decrease very fast when it high, and slowly decrease when it low.

Why dups can only be stress out but cant be more exciting?

[blash365]

This is merely a question of standardization. You could simply imagine your dupes at 50% stress being "neutral" and your dupes at 0% stress being excited. Put your baseline for productivity at that 50% stress and measure all other effects in relation to that.

What you are asking for is not a new feature, but a change of the numbers on the scale.