The General Instruction for the LotH has a word to the wise for those who look at Liturgy as a blank canvas on which to give free reign to their creativity and personal expression:
Those who pray the psalms in the liturgy of the hours do so not so much in their own name as in the name of the entire Body of Christ. This consideration does away with the problem of a possible discrepancy between personal feelings and the sentiments a psalm is expressing: for example, when a person feels sad and the psalm is one of joy or when a person feels happy and the psalm is one of mourning. Such a problem is readily solved in private prayer, which allows for the choice of a psalm suited to personal feelings. The divine office, however, is not private; the cycle of psalms is public, in the name of the Church, even for those who may be reciting an hour alone. Those who pray the psalms in the name of the Church nevertheless can always find a reason for joy or sadness, for the saying of the Apostle applies in this case also: "Rejoice with the joyful and weep with those who weep" (Rom 12:15). In this way human frailty, wounded by self-love, is healed in proportion to the love that makes the heart match the voice that prays the psalms.
A great deal of flexibility is inherent in most of the Church's liturgies, we need not seek to exercise options no on offer.