Most of the time I think this is great advice. There are so many people who will insist that you HAVE to do yellow cake with white frosting or you HAVE to wear a veil or you HAVE to send out black-and-white engraved invitations issued by "Mr. and Mrs. Bride's Father." It helps to have a balancing influence, one that encourages you to serve fruit tarts, forget the veil, and self-print colorful cards with your quirky custom wording if that's what you want.
A dessert buffet -- not the traditional wedding cake, but aren't you drooling? I am! Image from dessertcomesfirst.com.
But the dark side to the "make it unique" dictum is that sometimes, it's not liberating at all. Sometimes it's just another source of emotional pressure, one that ratchets up the difficulty of every wedding-related decision you make. You can't just go with a dress, some flowers, and a set of invitations you like. You have to LOVE everything. It all has to be "special" and "different" and "so you." And that's kind of exhausting. You know what? Sometimes it's OK to just grab something and go with it, rather than stress about how to make it "your own."
Furthermore, because brides are encouraged to get so wrapped up in the "personal details" of their weddings, any dissent from the choices they've made can be seen as a personal attack. My post on wedding dislikes was a ton of fun to write, but I have to admit I was kind of scared to publish it for fear of incurring the internet wrath of brides wearing pickup skirts and designing Tiffany blue and brown table settings. There seems to be so little tolerance for differences of taste and style in the wedding world that almost any statement of preference has to be prefaced or followed up by "this is just my personal opinion, of course not everyone does it this way, you should do whatever you want, I'm sure YOUR pickup skirt is gorgeous, etc. etc." (I'm guilty of it too!)
As A. said so eloquently last week, aesthetics are not ethics -- you are not victimizing your guests or being a horrible person if you choose white instead of ivory for the tablecloths (or if you forgo the tablecloths entirely for a picnic wedding). My own addendum to that is that someone else's aesthetics are not an attack on your aesthetics, or on you personally. After all, how can your wedding be "personal" and "unique" if you expect that everyone else would make the same choices you made?