Heaven is radiant and light. It is detached from earthly things, and it transcends beyond all ages. It is populated with The Trinity, Saints (people we know are in heaven) and Angels (spiritual beings with no bodily form). Heaven is perfectly ordered.
The way we think about heaven informs the way we think about the Liturgy. We believe that at the Holy Sacrifice of the Mass, we participate in the Heavenly Banquet. One way of thinking about it is that at the Mass we lift the veil between heaven and earth. We learn from Sacrosanctum Concilium that the purpose of Liturgy is to give glory to God (which is ordered praise, not self-expression), and to become more holy (sanctification). Becoming more holy means conforming ourselves to Christ, becoming a perfected version of ourselves. In order to this, we need God’s help, as we receive his grace in the Sacraments, especially the Eucharist.
Remember that Sacraments both represent and make present the invisible heavenly reality. If heaven is perfect, ordered, and transcends all ages, then hopefully our Liturgical celebrations (which are sacramental by their very nature) approach this heavenly reality. This means that the Mass should be ordered and radiant, but also detached from earthly things and transcend beyond all ages. There must be an “other-worldliness” in the Liturgy, because it is basically training us for what heaven will be like. Heaven is not about autonomous self-expression, or a giant party; it is perfect union with God, joined with the choirs of angels in their unending song of praise.