The opposite is the case. Missing Sunday Mass even once can be a huge problem. Here’s why.
Jesus said in Matthew 16:17-19, “Simon Bar-Jonah, I say to you that you are Peter, and on this rock I will build My church, and the gates of Hades shall not prevail against it. And I will give you the keys of the kingdom of heaven, and whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven.”
In this way Jesus gave authority to his Church, through Peter and his successors, to bind His followers to certain moral obligations. One such obligation, now referred to as a “commandment of the Church,” is the Sunday Mass obligation. Every Catholic who is able to do so is bound by a serious moral obligation to attend Mass every Sunday and holy day of obligation. This same Church has loosened these obligations slightly by allowing the Sunday obligation to be fulfilled by attending a Saturday evening Mass. Furthermore, every diocese other than the Vatican has an abbreviated list of holy days of obligation. In these and other ways the Church is exercising the moral authority given to her by Jesus.
Since the Sunday obligation is a serious matter, breaking it knowingly and with full consent of the will is a mortal sin. And we all know that every person who dies in the state of mortal sin (that is, with mortal sin on the soul without repenting) will spend eternity in hell. So intentionally skipping Mass because one doesn’t feel like going, or because there is a soccer game that day, or any other silly reason, is a huge problem; it can result in eternal damnation.
Before you object that this sounds unreasonable, please know that the Church releases from the Sunday obligation anybody who does in fact have a real impediment from attending. The Catechism of the Catholic Church explicitly states that those who are sick, and those for whom attending would require an inordinate sacrifice (e.g. travellers who cannot make it to Mass, those who have no choice but to work on Sunday, and those for whom getting to Mass would entail unreasonable travel or difficulty), and those who need to care for infants, the sick, or the elderly, are not bound by the obligation to attend Mass. After all, the only reason that Church binds obligations on us is for our benefit, and so if some circumstance makes the obligation become counterproductive, the reason for its existence is lost, and the obligation ceases. Thus we can see that the Sunday obligation is a loving commandment, not a burdensome one.
That’s why those who treat the obligation with contempt are thereby treating the authority of the Church with contempt, and thereby the Church herself, and thereby Jesus who founded it. That’s obviously a huge problem.