Cold Feet
I went to a wedding of my wife’s friend (who was the bride), and she was a good 40 minutes late getting to the altar with her husband to-be standing there with the groomsmen. Turns out, she was freaking out about marrying the dude that she never intended or wanted to marry. They divorced about 3 years later, and when asked why, she said she never wanted to marry him and didn’t love him, but she thought getting married would be fun. I never got to know the dude, but he seemed really heartbroken after that, poor guy.