Blessed Veronica of Binasco relates a similar experience: “Once,” she writes, “when, prompted by curiosity, I happened during the time of Mass to look at one of the Sisters who was kneeling near the altar, the Angel of God who is constantly beside me rebuked me with such severity that I almost fainted with terror. How threateningly he looked at me as he said, ‘Why dost thou not keep watch over thy heart? Why dost thou gaze thus curiously at thy sister? Thou hast committed no slight offense against God.’ Thus spoke the Angel, and by Christ’s command he enjoined on me a heavy penance for my fault, which for three days I bewailed with tears. Now, when I hear Mass, I never venture so much as to turn my head, for fear of incurring the displeasure of the Divine Majesty.” Now that was just for a glance! Think of the offence you give when you dress inappropriately
Lost Wanderer here is what a saint has to say about how important our dress is at Mass.
Saint Leonard of Port Maurice
***The Blessed Ivetta, herself a noble Flemish lady, had once a wonderful vision in church. Such a one as I have mentioned was not far distant from her during holy Mass, magnificently dressed, and the Saint was enlightened to see the disposition of her heart, and the vain, worldly, and even impure thoughts which came and went freely through her mind without any check. And all the while she perceived that there were evil spirits close to this self-complacent woman of fashion, who would at times seem to touch her lace or her ribbons as objects of which they had a care. The lady approached the altar-rails for holy Communion; the priest descended the steps, the adorable Sacrament in his hand, when, lo, the Saviour separated Himself from the sacred particle, and ascending heavenward, disappeared, refusing to enter the mouth of one so wretched as to carry her vanity into His very presence and there complacently to dwell on thoughts of sin. The Saint was made clearly to understand that the evil spirits who were near her found in her luxury and vanity of dress something congenial to their minds and easy instruments for her ruin, and that the Saviour refused to be given to her because of her sinful dispositions. Quoniam in malevolam animam non introibit sapientia, nec habitabit in corpore subdito peccatis, “For wisdom will not enter into a malicious soul, nor dwell in a body subject to sins” (Wis. i. 4). ***
catholictradition.org/Eucharist/hidden-treasure3c.htm