Seating arrangements are one of the toughest things to plan for a wedding. A lot of brides; once they've made several attempts at trying to seat their guests in some order; abandon the whole idea and let people sit where ever they want to help conversation flow'. This is more the kind of thing that works when only close friends and family are invited to the ceremony. If you've got a huge crowd coming to your wedding or all your guests don't know each other, then you need a seating plan.
The tough part about seating plans is that no one really wants to sit at the back or let's say next to the kitchen door. Then there's the fact that you don't want your guests to know who was a B list guest and who was the A list guest and if you put someone in the back with your great aunt, it'll be a bit obvious.