Not every Christian focuses upon the Seven Deadly Sins, but they are a usual illustration here of where some church weddings totally miss the point:
Greed - This includes simony (the selling of sacraments), which would surely include the extra costs incurred in selecting 'pretty' churches over local parish ones. Even if it didn't, then greed is in evidence everywhere else, in the tremendous expenditure involved when the bride and groom seek to create a fairy tale spectacle. Everything from special vehicles to dresses to extravagant receptions will tick the boxes here.
Pride - Vainglory used to be highlighted as a separate sin, until Pope Gregory amalgamated it into the category of pride. It means to attract all focus onto your own glory, though that will be a futile venture in its temporary nature. ALL brides are the most beautiful, until the next one comes along. We might also call it vanity.
Sloth - Spiritual laziness is at the center of many perceived normal wedding ceremonies. For those only attending church during these rites of passage, that charge is obvious. But when all concerned are more focused upon the whole spectacle of the occasion, rather than the solemnity of the oaths spoken before God, then all spirituality is lost.
Gluttony - For many guests, the best part of a wedding is the free food. That feast, wherein each wedding couple tries to out-do those who went before. People eat until they feel too full to move, and so much food goes to waste thereon. Then more food comes out later in the party. Not to mention the alcohol, which some Christian congregations prohibit in the spirit of temperance.
Wrath - Ever heard the saying that no wedding is complete without a fight or a feud kicking off? That's what happens when the happy couple invite people from all areas of their lives, chucking a clash of worlds and individuals who would otherwise avoid each other, into an environment of free-flowing alcohol.
Envy - And many of those fights begin when a) the thwarted love rival declares they should have been the bride/groom; b) the festivities are compared to those of a couple who were previously wed, like it's a competition; or c) some guest makes a pass at someone else's partner. Covetousness in all its dark glory.
Lust - See above, then couple it with the risque traditions surrounded with sending the bride and groom off for their wedding night.
But most of all, where was Christ in this order of ceremony? In a Christian wedding, He would be right at the center, which is what gives those rites its name.