I can't stress enough the importance of this lesson! DON'T WAIT! Go to frequent Confession, receive HIM in the Eucharist, give HIM an hour of your life in weekly adoration, and most importantly - THANK HIM for all HE has given you! You'll be ready then - when HE COMES AGAIN!
At the end of November and the beginning of December, the Gospel readings come from those teachings of Jesus toward the end of His life where He makes it clear that He will come back in glory and there will be a judgment.
(Just as an aside, this placement in the liturgical calendar can be a little misleading, because He actually says these things not long before the Last Supper. With their placement at the end of the liturgical year and the beginning of Advent, they take on a little different light, but they are still just as powerful.)
This is not only a part of the liturgical readings, it's also a part of the Mass itself. At every Mass, after praying the Our Father, the priest prays, "Deliver us, Lord, from every evil and grant us peace in our day. In your mercy, keep us free from sin and protect us from all anxiety as we wait in joyful hope for the coming of our Savior, Jesus Christ."
And in the Creed, we say, "He will come again in glory to judge the living and the dead, and his kingdom will have no end."
So the idea that Jesus will return is not foreign to Catholic thinking. For the most part, we don't dwell on it or speculate on when He will come again, but it is part of our heritage and belief. (I say, "for the most part," because there are some Catholics who do dwell on it and scour everything they can find to divine when the Lord will return.)
Why is this? There's a story of one of the saints that has a variety of tellings, but it gives in a nutshell how the Church lives this belief. It was either St. Francis of Assisi with his brothers out weeding in the garden or St. John Bosco playing billiards with a couple of friends. Either way, the question came up of what would you do if you knew the Lord was returning within an hour. One said, "I'd go home and reconcile with my family." Another said, "I'd go to Confession," and so on. They then turned to St. Francis (or St. John Bosco) and asked, "Well, what would you do?" "I'd keep on weeding" (or playing billiards).
In other words, they knew that what they were doing at that moment was what the Lord wanted them to do, and they also knew that they had all their affairs in order. Their attitudes teach a valuable lesson - live as though the Lord is returning at every moment of your life.