Emotion..?

Emotion would have to be the sketchiest form of gaining knowledge. While it is a way of gaining knowledge, I'm not sure how much knowledge we gain from it. I sometimes see it as more of a way of confusing the knowledge we already have. Our emotions cause us to second guess what were think we know and to at times become irrational and gullable. To me, emotion is mostly only used in art and such things, but not in say mathematics or science. I do not believe that you need to care about something to understand and believe it to be true. You may not have strong feelings for a subject, while you may still have a great amount of knowledge in that area. Upon this thought..I begin to question.. Are emotions really a good way to gain knowledge?