Wine is unique in that it not only satiates, it also gladdens the heart. Each type of wine has its own unique character, and when additional types of wine are consumed in company there is greater joy - and therefore a special blessing is recited.
The Sages teach that “jealousy, greed, and honor remove a person from the world” (Avot 4:21). These negative traits stem from the fact that a person is not satisfied with his own life and believes that his happiness depends upon exterior factors.
Every single event which takes place in the world has spiritual significance which beckons to be understood. When something good happens, one's joy is deepened by the fact that this good was not the result of happenstance, but the hidden hand of God.