We all believe to we are rational thinkers,
That said, our emotions have at least these two effects.
They change the weighting factors that we apply to the rational elements in our decisions.
They also impact even what elements we allow to come into view.
In the end, when our rational thoughts are restricted to a only issues that already align with our current thinking and apply weighting factors that further instantiate the same, then our emotions have served us well in maintaining our status que.