72. Pious exercises are part of Christian worship. The Church has always been attentive to ensure that God is glorified worthily through them, and that (the believer) derives spiritual benefit from them and is encouraged to the live the Christian life.
Some, but not all clergy do support, or at least, they do not forbid them:
The actions of Pastors in relation to pious exercises have been many. They have recommended and encouraged them, or guided and corrected them or simply tolerated them. Among the myriad of pious exercises, some must be mentioned, especially those erected by the Apostolic See, or which have been recommended by the same Apostolic See throughout the ages(Cf. SC 13). Mention must also be made of the pious exercises of the particular Churches “that are undertaken by order of the bishops according to customs or books lawfully approved”(SC 13); of the pious exercises that are practised in accordance with the particular law or tradition of certain religious families, or confraternities, or other pious associations of the faithful, since such have often received the explicit approbation of the Church; and of the pious exercises practised personally or in the home.
Some pious exercises which grew up among the community of the faithful and have received the approbation of the Magisterium(Cf. canon law 23), also enjoy the concession of indulgences(Cf., EI, Aliae concessiones 54).
What would be some examples of these? Signing oneself after receiving the Eucharist? Genuflecting upon entering a pew? May crownings, or a gesture to Mary during a wedding? Which ones do you see that work, and that perhaps don’t?
The full document, the Directory on Popular Piety and the Liturgy, is online at the Vatican site.