Let’s strip away the sacrificial and Eucharistic aspects of the Mass for a moment (eek, I will miss them dearly) and look at it from a narrow view of prayer and fellowship.
Christians are commanded to pray to the Lord. There is no debating this. In the Psalms alone there are dozens, if not hundreds of exhortations to “Praise the LORD!” and otherwise pray unceasingly. 1 Thess 5:17 reminds us in the NT. Likewise, if we are to follow the example of Christ, his repeated prayer is documented, and like all rabbis, He probably recited the psalms several times a day - obviously He knew them well! So we are commanded to pray.
We are commanded to have fellowship with other Christians. Psalms 95:1-7 is a prime example of this command - a communal call to worship. The Greek word, koinonia, is used 19 times in the New Testament. The call to fellowship is also indisputable.
So we are called to pray, worship and have fellowship. What is the minimum possible participation in these three things? Clearly it is Mass on the Lord’s Day. Clearly if we are to be spiritually enriched we will go further. But just like fasting on two days of the year, and abstaining on Fridays in Lent, we are called to go further and deeper in penitential practices if we really want to live out our call to authentic faith. We are called to volunteer in our parish, to forge friendships with other Christians, to pray day and night. These things are good but they need a basis, a bare minimum, a framework that must be prescribed for us on pain of mortal sin.
That is why the precepts of the Church are so easy to fulfill: they are minimums! Who receives Holy Communion once per year? I pray that we are all worthy enough to receive Him daily, and cheerful enough to attend Mass whenever possible, not just on Sundays or Holy Days of Obligation, and to supplement the “perfect prayer” with the Rosary and/or the Divine Office.
If you are the kind of person who looks around in Mass and sees only strangers and unfriendly faces, then consider living the Lord’s call more deeply. Get involved. Pray more. And take a bulletin on your way out, you might find something you like.