Are emotions rational? The issue of whether emotions are rational (or intelligent) is at the center of philosophical and psychological discussions. 

What is the mainstream take on the logic and nature of emotions? Or where might I be able to read more about the nature and logic of emotions?
Our evaluation of the rationality of emotions depends on some social norm about the behavior and context of the behavior. On the other hand the somatic marker hypothesis states that there is logic in the inner workings of emotions. To illustrate somebody having an outburst while on his job may appear irrational to the public, even though there is rationality how this emotion was born. 

The somatic marker hypothesis states that our decision making process is influenced by emotions (Damasio, 2000). Behavior that are associated with good outcomes are more likely to be repeated. Emotions and their bodily representations (somatic markers) serve as biasing signals for decision making. The case of Phineas Gage, a man that had an iron rod driven through his skull is used as example of not being able to use emotions in decision making, due to damage to the vmPFC.

According to the somatic marker hypothesis emotions and bodily changes(somatic markers) become associated with previous outcomes. This associations guide subsequent decision making processes. The markers can be activated through two distinct pathways. The first one is the body loop, where changes in the body are relayed to the brain. Being triggered by some sensory experience would fall into this pathway. The second pathway is as-if-body loop, where cognitive representations activate emotions. I think that the somatic marker hypothesis says emotions are embedded in our rationality rather than saying our emotions are rational. 

To summarize I believe it is necessary to uncouple the evaluation of the rationality of some behavior and the processes guiding emotions.

References

Damasio, A. R. (2000). Descartes' error: Emotion, reason, and the human brain. New York: Quill.