"What in the world could they have been thinking?"

Definitely words you DON'T want to hear your guests uttering at your wedding. But despite your best intentions, sometimes things slip through the cracks. Sometimes you make a really silly mistake that, if you had just stopped and thought about it for a few minutes, never would have happened. The problem is that many brides and grooms are so darn busy trying to manage everything else that's going on - from housing out-of-town guests to dealing with last-minute cancellations or additions to the guest list -- they simply overlook the obvious. That's when smart people wind up making really stupid mistakes. Here are seven common slip-ups that can ruin an otherwise perfect ceremony.

1. Failing to Thank the Guests

They came to the wedding. They brought gifts. They stopped and congratulated you and took time out of their busy lives to help you celebrate the joining of you and your beloved in a new life together. Don't leave the reception hall without saying thank you!

2. Speaking While Intoxicated

This one should be a new form of misdemeanor. If your wedding traditions include the bride or groom making a speech to the assembled guests, do it before you enjoy the free bar. You'll be thankful later when you watch the wedding videos, and you won't have to apologize to people you don't remember insulting.