Anything Loud or Garish
People are there to look at the bride, not your obnoxious hat/dress/purse/shoes/eye shadow. Donning loud or garish apparel and accessories is a surprisingly common method of wedding-crashing women use to upstage the bride. Your outlandish choices might not be directly comparable to the bride's traditional white garb, but everyone -- including the new Mrs. -- will likely take them as a sign of extremely poor taste or a desperate call for attention. You'll get people talking, but you probably won't like what they have to say!