I must be an oddball !!! I sometimes wander in my thoughts during the Homily, as my Priest has a heavy accent, and I can’t always follow what he’s saying. I’ve started gazing at the large crucifix behind the Altar and praying when this happens. During the Mass itself, and especially the Consecration, I am very focused on what is happening on the Altar and worshiping the Lord throughout. Same during the hymns, and after Holy Communion.
I used to wander mentally, but for several years now I have been very focused. Partly, I think it is because I could rarely attend Mass for 3 years while caring for my terminally ill husband. After his death, I became very focused and so grateful for the comfort I received during Holy Mass! I also went back to being an Extraordinary Minister at Mass. I only notice a wandering mind when one of my servers or other Extraordinary Ministers whom I schedule do something wrong. I notice it immediately, and begin thinking about how to kindly correct them, then realize I’m taking my attention away from the Liturgy and immediately try to concentrate again.