I've been to several wakes and funerals recently.  Never pleasant for anyone, they're often much needed wake-up calls to remind us to focus on the important things. “Rest in peace” is the traditional phrase used when someone dies.  On prayer cards, flower arrangements, offered by friends and relatives, everyone uses “rest in peace” as a simple type of prayer wishing an end to suffering and difficulties for the person who has now completed their early journey.
It's well meaning, of course, but I've never completely understood the phrase.   For those of us who are very active and always on the go, never really resting apart from sleeping, “rest in peace” sounds like simply being asleep—or like not existing at all.  Actually, I used to think that's what it meant and I wonder if others might think the same. As a poorly catechized revert,  I assumed that “rest in peace” meant, “until you are raised on the last day, may you sleep/not exist peacefully.”
That was before I learned that the soul doesn't die at all—not even for a short time. 
It was after I lost my mom twenty years ago that I was searching, desperately searching, to know if she still existed somewhere after death. I wondered if she had to wait until “the last day” when our bodies are to be raised again.  I so wanted to believe that she still “was” somewhere, that she lived on. My searching wasn't in vain, for I finally realized the good news that anyone who dies in friendship with Jesus Christ goes immediately to either purgatory or heaven. There's no not-existing at all, because the soul continues.  So that's what everlasting life means!
The Catechism refers to a particular, individual judgment for each person immediately upon their death: "Death puts an end to human life as the time open to either accepting or rejecting the divine grace manifested in Christ. The New Testament often speaks of Judgment in terms of the final accounting with Christ at his second coming but it also affirms that each of us will be rewarded immediately after death in accordance with our works and faith. Each man receives his eternal retribution in his immortal soul at the very moment of his death, in a particular judgement that refers his life to Christ: either entrance into the blessedness of heaven—through purification or immediately—or immediate and everlasting damnation." (CCC 1021-1022)
Still, I thought, merely resting in peace sounded kind of boring.  Of course it's great to look forward to no pain, suffering, trials at all.  But in the absence of all the 'stuff' that makes up our earthly lives now, what would resting in peace really consist of? I wanted to believe that heaven was better than just sitting around resting.
Again I wasn't disappointed.  While our minds were not made capable of imagining the place prepared for us, we know that it's a place of pure joy: "Heaven is the ultimate end and fulfilment of the deepest human longings, the state of supreme, definitive happiness" (CCC 1024). We will actually meet God. And we will meet the Blessed Mother, the saints, and again be with our family and friends who have died before us. Now this is starting to sound heavenly!
Being in the presence and peace of God is called the beatific vision.  And that is promised to those who love Him, eternally. St. John the Apostle tells us, “We shall be like Him, for we shall see Him as He really is” (1 John 3:2).  St. Paul says, “That eye hath not seen, nor ear heard, neither hath it entered into the heart of man, what things God hath prepared for them that love him” (1 Corinthians 2:9).

Pope Benedict XII emphasizes the immediate judgment, with the resurrection of our bodies only later at the end of the world.  He also assures us of the happiness of our family and friends who passed to eternal life before us:

“By virtue of our apostolic authority, we define the following: ‘According to the general disposition of God, the souls of all the saints ... and other faithful who died after receiving Christ’s holy Baptism (provided they were not in need of purification when they died, . . . or, if they then did need or will need some purification, when they have been purified after death, . . .) already before they take up their bodies again and before the general judgment - and this since the Ascension of our Lord and Savior Jesus Christ into heaven - have been, are and will be in heaven, in the heavenly Kingdom and celestial paradise with Christ, joined to the company of the holy angels. Since the Passion and death of our Lord Jesus Christ, these souls have seen and do see the divine essence with an intuitive vision, and even face to face, without the mediation of any creature.’” (Cf. Benedict XII, Benedictus Deus, AD 1336).

And now I can say “rest in peace” understanding the happiness that implies.