As someone who is planning a wedding I found these to be the kinds of traditions I should avoid. From Brides:
In Ireland when the bride and groom are dancing the bride must keep both feet on the floor at all times. Irish folklore states that if they don’t, evil fairies will come and sweep her away
I guess that leaves out Irish step dancing at the wedding reception.
Brides and females of the Tujia people in China take wedding tears to a whole different level. Starting one month in advance the bride starts to cry for one hour everyday. Ten days into the waterworks extravaganza her mother joins the picture, and 10 days after that grandma does the same. By the end of the month every female in the family is crying alongside the bride.