This 2014 Harvard/Princeton research studied brain areas as people made choices among multiple good options:

“Our results show that choice conflict can at least lead to substantial short-term anxiety, that this anxiety increases with the number and value of one’s options (potentially enhanced by time pressure), and that it is not attenuated by awareness of the objectively negligible costs of a “bad” choice.”

There was a problem with the way the researchers evaluated “positive feelings” through the subjects’ computerized self-reporting. The subjects’ cerebral assessments of “positive feelings” didn’t match their limbic system functional MRI measurements.

These discrepancies showed that what the subjects assessed weren’t emotions originating from their limbic system or lower brains. “Positive feelings” were, instead, constructs of the subjects’ cerebrums.

“This is what I think I should be feeling” may have been a more appropriate characterization of the subjects’ assessments.

The study had better accuracy when fMRI measurements showed that limbic system areas were more activated in people who self-reported feeling more conflicted at the time they made their choice. The conflicted subjects were also more likely than subjects whose limbic system areas weren’t similarly activated, to reverse their choice when given the opportunity.

http://www.pnas.org/content/111/30/10978.full “Neural correlates of dueling affective reactions to win–win choices”