That is what Jesus promises in heaven but that is not all. The Kingdom of God is not just heaven. It is also realized to a lesser extent in the church right now. It is still like marriage. You get out of it what you put into it. The joy comes from giving yourself wholeheartedly. Yet it is there and it is real. The greatest love possible is available for us to embrace right now through obedience, through the sacraments, through prayer, through serving, really just making any serious effort to love God. It is there to bring us abundant joy and peace that passes all understanding. This is what being a Catholic is supposed to be.
Then there is the uncomfortable part of the gospel. Not everyone goes to this wedding. Some refuse because they are too busy. People who want to get serious about their faith but there just is never enough time. Career issues are mentioned. Nothing wrong with trying to get ahead but refusing to come to the wedding supper of the lamb? They say 70% of Catholics miss mass on any given Sunday. The church says this is gravely immoral. That is that it could cost you your eternal soul. People say that is a bit harsh. Is it? Precisely the same Jesus is offering Himself to you at mass that is offering Himself to you in heaven. If you don't want Him in this life why should Jesus think you want Him in the next?
Then we have those who actively oppose the King's messengers and beat them and kill them. Jesus talks about the King sending his troops and killing those people and burning their city. Now this obviously refers to the Jewish leadership that ends up being slaughtered by the Romans when Jerusalem is destroyed in 70 AD. Still we have this notion that God actively causes the destruction of those who oppose Him. With the Jews it took decades. So we are not talking about a God who crushes you as soon as you make a false move. Yet He does do justice. There is warning. There is amazing forgiveness. Yet there still is justice.
Then there is the man with the wrong clothes on. What is going on there? What kind of person goes to a wedding not dressed in wedding clothes? Someone who is not interested in the bride or the groom. Someone who just wants to eat and to party. That is not the way we are to desire heaven. We should not be desiring superficial pleasures. That is not what heaven is about. Heaven is about being close to God. God will invite everyone but they need to show their desire to be close to Jesus and His church. They need to show it by their actions. Dressing for an occasion is a basic way to indicate you attitude. Our desire needs to be strong enough and sincere enough to change out behavior. Not to earn salvation. You don't earn a wedding feast by dressing appropriately. Just to really embrace it rather than merely giving lip service.