One of the best pieces of advice I received when I was planning my wedding was to plan for a wonderful day, not necessarily a perfect day. No matter how much you plan, there will be those unexpected things that will just happen. If you are hoping and preparing for a perfect day, you will soon be disappointed when things don't turn out as you plan. Instead, look forward to a wonderful day that celebrates the love between you and your fiancee, and you can take unexpected happenings in stride.
(Photo acquired from Brighterorange's Flickr photostream in the Creative Commons)