Well, I can think of a lot from the day of our wedding! Lol!
Let's see...we forgot to pay the officiant and photographer, we didn't fully charge the camcorder a friend was planning to use to record the ceremony, my bridesmaids forgot to tell me they took my purse with me to the reception while I was taking pictures with my husband (just a little scary), we were supposed to share a glass of wine during the ceremony (a Romanian Orthodox tradition) and we forgot the wine...I'm sure there were a lot more. In the end, not one thing mattered. We were so happy that we barely noticed a bit.
As far as planning and preparing goes, I made some typos on our programs and ordered a dress online and realized upon trying it on that it just wasn't for me.
As bride name change experts for 17 years, we have found that many brides think that the "Pronouncement" or "Announcement" during the marriage ceremony ( I now pronounce you husband and wife or Ladies and Gentlemen may I present to you Mr. and Mrs. ), legally changes her last name. This is incorrect! There is an entire complicated process of name change notification which must be completed. That is why our bride name change software has 32 pages of step-by-step, many name change forms, on-line tools, and a call center staffed with name change helpers to answer questions. A Bridal Oops... the words of the wedding ceremony do not "change a woman's last name " to that of her husbands!
I can tell you about my wedding event 28 years ago. Our best man fainted during the ceremony. Here's the situation, it was July 24th, the middle of summer and extreme Texas temperatures. The church was not as cool as it should have been because they failed to turn the air conditioner on early enough. My husband and all of his groomsmen (except the best man) had a few beers prior to the wedding. Our best man wouldn't drink a drop. We believe the beer helped the other guys. Anyway, here's the scene, we are kneeling on the prayer bench and our vocalist was singing "The Lord's Prayer" and down goes the best man -laid out flat over the train of my dress. At the time I worked at a clinic and there were a lot of nurses and other medical personnel in the audience. Half the audience jumped up to retrieve him. My father in law jumped up and took his place and he ushered out the maid of honor at the end. They drug the best man out the door behind the sanctuary. We still hold this over him to this day!
The only other "biggie" is that my mom was loading the top layer of our wedding cake in the car so we could freeze it for our 1st anniversary. Well, it slid off the roof of the car and we didn't have cake to freeze. Other than these things, the day was perfect.
