Notice that II Thessalonians 1:8 says that God will take vengeance on those who do not obey the gospel of Jesus Christ. This idea has a strong tie to the book of Revelation, as the gospel of Jesus Christ is the "good news" that He brought. His good news is not primarily about Himself, but rather it is the message that He brought from His Father about the Kingdom of God being established on earth (Malachi 3:1; Matthew 4:23; 9:35; Mark 1:14-15; Luke 4:43; 8:1; 16:16-17). After the gospel is preached in all the world as a witness to all nations (Matthew 24:14), God will be justified in punishing all of those who reject it. The end of this present world will come when God takes vengeance on those who have heard the gospel message—which, at that point, will be everyone alive on earth—but who refuse to repent and submit to God's rule on earth.
The tie to the book of Revelation is that the unveiling of Jesus Christ, when He removes man from governing the earth and takes that responsibility to Himself, is the fulfillment of the gospel message that He brought. When Christ is revealed, the Kingdom of God will be at hand. Revelation fills in the explosive details of how the governments of this world will come under the rulership of God.
Even though the word gospel means "good news," people typically do not think of the book of Revelation as being encouraging or uplifting. For most professing Christians, the gospel that Jesus preached is not good news. They prefer a gospel that is limited to the forgiveness of their sins. When they hear that God's Kingdom includes repentance and obedience to His laws, they cannot tolerate it (Romans 8:7). For those who will not obey the gospel, the book of Revelation is not good news at all, because it foretells their judgment for idolatry and disobedience.
For true Christians, though, this book iswonderful news! It may not be "good" news in the sense of being pleasant, enjoyable, or attractive. Instead, its news contains a zealous, righteous goodness—an active pursuit of what is good for mankind, a deliberate and forceful bringing to pass of those things that will make life good for everyone. The entire creation will rejoice when the present principalities, powers, and broken governments of men are replaced with a King who will powerfully impose all that is good upon a sin-sick world.