on informal styles of worship
This usually involves singing of songs written in the modern idiom, very often from Protestant origin, which people would term "Praise and Worship".
I am uncomfortable with this term as used in this way, because the Church teaches that the ultimate Praise and Worship is done through the Liturgy, at Mass and at the Divine Office. I'd prefer some other name, maybe "songs of praise session".
I am uncomfortable with such a form of worship for two reasons:
(1) the choice of songs often leaves much to be desired, with very bizarre texts sometimes chosen eg. those that suggest "Jesus is my boyfriend". This is because we pray as we believe, and the texts of the songs have to reflect our beliefs.
(2) such a session often leaves the participants all emotionally fired up. However the effectiveness of prayer is not measured by one's emotions.
Two objections to my two reasons have been expressed to me:
(1) one should not "intellectualise" the process of prayer and worship
(2) everyone has the right to express his faith in his own way
I answer that
(1) we cannot divorce our intellect from the practice of the Catholic faith.
(2) while this is true, we must also not ignore the fact that we have to seek guidance and not be left to find our own way towards holiness.
Nevertheless, I'd leave those who prefer this style of worship alone.
just some thoughts. will revise this post if necessary.