I recall a few years ago hearing a 70+ yr old revert to the Church (he'd been away from her for 50 years) trying to persuade some of the other men at the Catholic Club to go back to Mass. The men were grumbling that Mass was boring and they couldn't see why they should go, they didn't feel any different for not going, God hadn't smited them.....
Our zealous revert retorted with "Well shaving's boring, but you still have to do it."
Whilst it may not be the most convincing argument, it does hit on a few important facts. Firstly obedience - we have to, the Church tells us that we should go each Sunday. In a "me me" world, obedience is difficult, you will get a "But why?" and as your answer to that is not good enough a "prove it" will triumphantly be exclaimed. You will have no answers that will convince...Convincing a waverer of the importance of obedience is like convincing the child who has yet to burn themselves on a hot plate not to touch it.
Christ proclaimed "Do this in memory of me" at the Last Supper. We want to remember those we love, we should attend Mass as the greatest possible memorial of His death and resurrection.
Yes, but Christ didn't say go each week, put up with over long sermons and in-jokes from priests over chummy with the great and good in the front pew.
This brings me onto the second point made by my zealous revert. Routine. Consider our human selves; in adult life, prone to grow hair where it isn't wanted and lose it where it is wanted, we need grooming. If we leave ourselves to the tender mercies of all the world has to offer, surely our souls can become bedraggled and develop plenty of "unwanted hair". Mass, even if you feel unable to attend communion, even if your faith is flagging (especially if your faith is flagging because your effort is like the widow's mite) , must be good for your soul. Making the effort to leave the house, join others, trying to focus on the supernatural, loving Jesus and doing as he asked.....your soul will gain strength even if you can't feel the benefit.
St Paul says in 1 Thessalonians 5:8:
let us put on faith and love for a breastplate, and hope of salvation for a helmet.
When we lose our faith, or it starts to waver, we can still have love as a breastplate protecting our own hearts (love Jesus and do what he says even if you can't feel where it is going).
Protect our heads with the helmet of hope of salvation. All our rational thoughts and difficulties need prioritising, St Paul is not asking us to believe in salvation, just hope for it....Hope is expectation and desire.
What better thing to desire than heaven?
Mass should be a foretaste of the banquet of heaven, it may often seem to fall far short, this collectively is our fault, the fault of the Church, for not desiring heaven enough.
Please read terry Nelsons post here for further help.