Matching the colour of your outfit to the colour scheme of the wedding you're attending. I've had two people ask me what my colours are so they can match 馃槀 I know bridesmaids are supposed to coordinate but everyone else?!
Sounds crazy but nowadays you never know. In my church we have small family and close friends only weddings at home and than the following afternoon usually a Sunday we have a big potluck reception with the entire church invited.
I did that, only to find out it was a massive insult to the bride. :-/ I had told her what I was planning on wearing but she didn't ask me to change it or explain 3 months prior! :-/