An argument that the sign of the cross should be made from left-to-right in Roman-rite churches:
It’s not that there’s intrinsically anything better about making the sign of the cross one way or the other. But the liturgy is, among other things, about the scattered sheep being gathered into one sheepfold with one shepherd. The words and actions performed by the community show forth the unity among them and at the same time bring about that unity. The liturgy is not the time to indulge personal preferences and idiosyncracies, but to participate in a sacred action that manifests the unity of the Body of Christ.
I can’t quite come up with the quotation, but St. Bernard of Clairvaux in his Steps of Pride and Humility says something like (paraphrase) ‘The proud monk takes greater delight in fasting alone for one day than in fasting for an entire week with the rest of the community.’
The idea being that, sometimes it’s greater mortification to put the community’s practice ahead of one’s personal preferences.