Emotion vs. Intellect

One of the most powerful factors governing peoples decisions and actions is emotion. The media, especially advertisers, design content that plays on our emotions. Often times, little consideration is given to fact. I believe that emotions in and of themselves are neither good nor evil, it is the way in which we use them that determines this.
Take love, for example. Though not simply an emotion, love can be either very good or very bad; loving one's children is a good thing, while loving an addictive drug is not.
Anger again illustrates positive and negative aspects of emotion. Concerned anger over the negligence of a friend which places him in danger may spur the angered person to helpful action. On the other hand, being quarrelsome and easily aggravated can lead to isolation from other people and general unhappiness.
From my experience, people today don't cultivate their emotions. Many people don't make attempts to reign in their anger or curb their love of obviously harmful activities before they become trapped by addiction. There are obviously other factors, such as brain chemistry or the circumstances of childhood that also influence this. It makes them much easier for salesmen to exploit. Without having to rely on fact, they can manipulate peoples feelings in order to lure them into a sale.
I'm writing this, actually, because of an emotion. I get annoyed when people I'm having discussions with say things like "this is only my opinion, but..." I'm probably being too critical, but they were trying to construct logical arguments and that is a horrible way to go about it. Arguments shouldn't be based solely on feelings. For example, some people might say "I feel that George Bush was the greatest President in living history," and upon being asked why, they say "I don't know, thats just how I feel."
Am I being too critical?