It pleases God to keep the veil drawn on what the end of time and life in heaven will be like. Mostly. Even though he is holding back on information about the Great Surprise, just like a parent who makes her kids wait until Christmas to unwrap presents, he does put out little bits of the puzzle to encourage us, keep us fired up, and help sustain us in our struggles.
St. Paul more than most was allowed to see what the end of time will be like and just how the long-suffering children of God will be reunited with their Father: “The Lord himself will come down from heaven, with a loud command, with the voice of the archangel and with the trumpet call of God, and the dead in Christ will rise first. After that, we who are still alive and are left will be caught up together with them in the clouds to meet the Lord in the air. And so we will be with the Lord forever” (1 Thessalonians 4:16,17).
Notice that for Christians, the return of Christ will bring no terrors. It will be like a family reunion. We will finally get to see and touch the One who was incarnate for us, lived for us, suffered and died for us, and rose again to guarantee our resurrection. We will also be gathered with the vast sea of other believers, the dear people with whom we will spend eternity.