(Not to be sarcastic, but cute) I didn't downvote you, but I am going to thoughtfully disagree.

Our emotional intuitions are largely shaped more by evolution than by our own values and preferences.

Well, if that were the case, people would have the same emotions about the same things, but actually, different people have different reactions to different things. (That's because they value different things.)

If emotions were great cognitive tools, we wouldn't need to discover rationality

Emotions are responses to values (as patio11 said, rightly, in his talk). You need to use reason to figure out what you value. Once you do, your emotions follow therefrom. But "what you value" is actually very complex and context-dependent sometimes, which is why emotions are so useful to give you a snap summary of what could otherwise be a very complex situation to analyze thoroughly.

It's certainly the case that your emotions can be "wrong," but they just follow the thinking you've done previously, whether that thinking was deliberate or accidental.

Thanks, but I think I must have not made my point effectively. I'm well aware that we have biases and being burned can make one avoid something "illogically". But if you are trying to sell something, then emotional appeal contains shorthand, dense information. As an example, see edw519's post in this same thread and the remarks of his he linked to: http://news.ycombinator.com/item?id=2372514 In short, he says he wants someone "shaking with excitement" to use his product. "Shaking with excitement" conveys a great deal of info about the value of the product with very little effort. If you can sum up the value of your product so succinctly and powerfully, then there is a kind of density of info of the sort that influences decision-making (ie leads to sales).

Does that make more sense?