Sometimes Mass can seem boring to me, but I still attend Mass every week. Is it a sin to have thoughts during the Mass of looking forward for it to be over? By that, I mean thinking like, “Okay, it’s halfway done.” And if so, is it a mortal sin or a venial sin?
I wouldn’t say that it is a sin in of itself, but it is a really serious defect.
I can appreciate that it is difficult to elevate your spirit to heaven in the midst of a liturgy that is celebrated in a lackadaisical fashion, a celebrant who ad libs the lines, music that is best used as a natural source of saccharin, a homily that is uninspiring (at best) and heretical (at worst), a congregation that is in competition with each other on who can dress the sloppiest / skimpiest, sitting next to a mother who believes it is her job to feed her seven year old child cheerios…and so on. All very understandable and legitimate distractions. In those circumstances, it is fully understandable that one would want to leave the situation as soon as possible (and for me, that would include leaving in disgust)
But none of those reasons is why we are there.
We are there to participate in the heavenly liturgy. To give true worship to God. To participate in the re-presentation of the eternal passover sacrifice that occurred on calvary and to offer the Victim to God in reparation for our sins and the sins of the world.
Mass is significant (in a cosmic sense as well as being important for your soul).
A book recommendation is The Lamb’s Supper by Scott Hahn. Though I’m not the biggest Scott Hahn fan in the world, this book really lays out the spiritual significance of the Mass with full scriptural references.
Once you have been able to understand the theology behind what is happening at the Mass, try to find a reverently celebrated Mass. If you are anywhere near the DC area (your location says Maryland, so you should be), try to go to a noon Mass at the Basilica of the National Shrine of the Immaculate Conception on the campus of CUA. It is a whole lot easier to put yourself in the proper spiritual position when you are participating in the Mass in a glorious place with glorious music and with a liturgy celebrated well. (Assumption is just two Sundays from now…that would provide a good opportunity to try this)
Once you realize that the same thing, on a spiritual basis, is happening in your local parish with its cheesy music, lousy preaching, and horrible adherence to the rubrics, (along with parishioners who don’t seem to care)…it is a whole lot easier to filter that junk out and elevate your spirit to the heavens and offer yourself as a living sacrifice (Rom 12:1) with Christ and to worship God in spirit and in truth (John 4:24), regardless of the distractions that may be trying to pull you away from that.
If, on the other hand, your understanding of the liturgy and/or the lousy quality of the liturgy in your parish is not the cause of your problem, then you may need to simply do a lot of prayer during the week…that God may enlighten your eyes of understanding (Eph 1:18).