Worst one ever was my exBIL's wedding. He was nearly 50, she was 24. He was a complete arse who still thought he'd make it as a musician one day, sort of 50 going on 17. She was a beautiful but naive black American girl he'd met 'on tour.' They'd only ever spent a few weeks together but if she was going to move to the UK, they had to get married.
Her family disapproved so didn't come. Two of her friends, Puerto Rican sisters came as her bridesmaids.
The wedding was in a chocolate box church an hour's drive from the city, then reception in a barn conversion with catering by a few of BIL's friends. Nice enough food.
The bride was the only black person at the wedding. 50 guests, family and friends of exBIL, all white and just the 2 bridesmaids for the bride.
After the B and G set off for their honeymoon, we had to deal with 2 sobbing bridesmaids who had no transport, and no idea where they were. They were supposed to be staying at the G's flat back in the city until their flight home, but no one had arranged anything.
We had a car full, 3 DC under 8, so couldn't help, but said we'd ring a taxi for them. It turned out they had no money either. We and my other exBIL (nice chap) sorted them out.
I knew it would never last, gave them 18 months. They actually stayed together longer than my ExH and myself in the end. Never saw that one coming at the time. We're all divorced now, though.