From a ruined white gown to the flowers never arriving, lots can go wrong on a wedding day. But some of the worst wedding day mishaps come from the cringe-worthy things guests decide to do.

Whether it was at their own wedding or at a ceremony they attended, these 15 people have witnessed some of the most ridiculous wedding day disasters:

1. A very awkward speech

"Give a speech in which you make allusions to an attraction/secret relationship between yourself and the bride. Easily the worst wedding speech I've ever heard. Just so awkward."

2. Oh, mother-in-laws

"I've been to two weddings where the new mothers-in-law wore white. Why not just wear a shirt that says 'I Hate My New Daughter'?"

3. A change of tune

"Don't go up to the organist during the church ceremony and offer a big tip if he'll play the funeral march for the recessional instead of what was chosen."

4. Click-WHIRR

"We got married 25 years ago and my grandmother had a Kodak Disc camera which was old, even then. It made a loud ~click~WHIRR~ sound every time she took a photo. Our ceremony was punctuated by click~WHIRR~click~WHIRR~click~WHIRR."

5. Don't be that guy

"[He] drank a quart of whiskey before the ceremony, refused to put on a shirt during the ceremony and then sat in your car and blast techno the whole time because he was asked to leave. Someone did this at a wedding I was at on Saturday."

6. "I'm pregnant!"

"We had somebody announce a pregnancy at our reception ... Then she started yelling at people because they were not paying attention to her. I was so embarrassed and angry that I got up and walked out of my own reception. Other than that it was a pretty great party."

7. Please...just don't

"Ask when it's your turn to kiss the bride."

8. Even worse than wearing a white dress

"Show up wearing your wedding dress to another person's wedding. Happened at mine."

9. The uninvited guest

"Bring someone to the wedding who wasn't invited ... They both show up in Pokemon sweatshirts and sweatpants and end up getting obnoxiously drunk. The uninvited friend drank 14 beers (that we had to pay for) and ended up spending 10 minutes hanging out at out head table talking about pudding. I could have killed them both."

10. Let's just stay away from exes altogether

"Don't almost call the bride the name of the groom's ex-girlfriend in the best man speech. It happened at a wedding I attended. Awkward!"

11. I feel sleepy already

"Start a toast with 'webster's defines marriage...'"

12. Sit down, grandpa

"My wife's grandfather (raised an objection when the priest asked). He told everyone 'my granddaughter has been terrified of clowns since I can remember. Well Jacosion (the groom) is the biggest clown I've ever met.'

Then he sat down.

It was meant as a joke, and I knew he had something planned beforehand. Everyone had a good laugh."

13. Whoa there, mom

"Wear all black, and show up with a freshly shaved head, especially if you are the groom's mother. This happened to me and my husband spent the wedding telling people he didn't know her."

14. I object!

"Happened to a close friend:

Groom's family objects to the marriage (does not like the bride), goes to the wedding anyway (drove hundreds of miles to the venue), and asks the wedding coordinators and the priest if there's a chance the wedding can be called off."

15. Hiring family

"Never ever, no matter how much they ask, say a family member with a budding photography career can photograph your wedding. My mom's brother asked her if we would use him. The photos were so bad. He had his 12 year old daughter be the videographer. She danced around with the camera the entire time. I do not have a video of my wedding. My uncle took pictures of his girlfriend during the ceremony, meet/greet, reception. I have a handful of pictures that weren't bad, but I definitely was the one who edited them. I didn't even get hard copies of the photos. He gave them to me on a disc (completely unedited) after I had to meet him at Starbucks and sat trapped for an hour listening to him whine about his foot. Oh and he charged us $200 after he said he'd do it for free, and he said that was the family discount. Don't hire family."

Yikes! What's the worst thing you've ever seen happen at a wedding?

Editor's note: Reddit comments were edited slightly for grammar, content and punctuation to help boost readability.