"Why Your Biology Runs on Feelings"

"Whether feelings correspond to positive or negative ranges of homeostasis, the varied chemical signaling involved in their processing and the accompanying visceral states have the power to alter the regular mental flow, subtly and not so subtly. Attention, learning, recall, and imagination can be disrupted and the approach to tasks and situations, trivial and not, disturbed. It is often difficult to ignore the mental perturbation caused by emotional feelings, especially in regard to the negative variety, but even the positive feelings of peaceful, harmonious existence prefer not to be ignored... 

It is often asked, not unreasonably, why feelings should feel like anything at all, pleasant or unpleasant, tolerably quiet or like an uncontainable storm. The reason should now be clear: When the full constellation of physiological events that constitutes feelings began to appear in evolution and provided mental experiences, it made a difference. Feelings made lives better. They prolonged and saved lives. Feelings conformed to the goals of the homeostatic imperative and helped implement them by making them matter mentally to their owner as, for example, the phenomenon of conditioned place aversion appears to demonstrate. The presence of feelings is closely related to another development: consciousness and, more specifically, subjectivity."

http://nautil.us/issue/56/perspective/why-your-biology-runs-on-feelings

This is too long, I recommend skimming, but it addresses interesting points.