Everyone is going to want a piece of you the day before your wedding...
... and you need to prepare yourself in case you normally don't deal well with this type of situation.
One of the things that really surprised me was how stressed out and irritable I was the day of the rehearsal. I had done SO WELL throughout the entire engagement ~ in my opinion, I was definitely not a bridezilla. And I know people close to me were worried I would turn into one. :) Now, don't get me wrong, there were times when I was stressed out. BUT. During the entire year of the engagement, I was in my last year of getting my MBA. The hardest semester of my life just so happened to coincide with the time many of our large to-do items were due (i.e. sending out save-the-dates, creating & mailing invitations, settling on the menu, finalizing floral arrangements, etc, etc). Somehow, I made it through my last semester & graduated without a major meltdown. In fact, the entire summer went by without a meltdown.
Until rehearsal day. [I have my thoughts captured on camera, too. After the rehearsal, I drove to the dinner myself and totally let loose on my little Flip camcorder.]
I won't go into details, but all you need to know is this: As a bride, there will be moments when you want to yell, make faces, and say nasty things to at least one person involved in planning your wedding. No matter how strong the urge, do yourself a favor and take a time-out. Walk away for a second, take deep breaths, write in a journal, drink a glass of wine (just not before your ceremony! you need to be sober in order to savor those vows!)... do whatever you need to do so that you don't say something you will regret later.
Another thing you should know: I was AMAZED (seriously) at how quick I was to forget every little thing that went wrong prior to my wedding. When I walked down the aisle and saw TR's cute smile, nothing else mattered. I couldn't think about anything else except for marrying my best friend, and hopefully you will feel this way, too!