We'll start with: "The Omniscient Guest." This is the guest who knows so much more than anyone else at the wedding, including all of the wedding professionals. Everything you're about to read has happen to me at one of my weddings. ;-)

No, you cannot move the tables with the 50 pound centerpieces closer together to make one big table. I had a wedding where to my horror I had guests trying to do just this. Really? You can't sit 8 feet away from your friends? It's just for dinner!
Never try to grab a microphone out of the hand of the DJ or Wedding Planner. We're not going to hand over the mic to a drunk person. Or a sober person for that matter. Let the MC make the announcements.
Don't interrupt the wedding planner during a most busy time and ask for explanations as to why this or that is happening. What am I supposed to say? We don't have a coffee station because your friends didn't spring for it, or think it necessary in the 90 degree heat? She's not dancing with her father because he's estranged and was lucky to have even been invited? There's no alcohol because the groom is an alcoholic? Let it be. Just be happy and have a good time.
Lastly, please don't tell me what you did at your wedding, your friend's wedding or your sister's wedding. To be blunt, I don't care. This isn't your wedding and we're doing it the bride's way. Not to mention, I have one or two weddings under my belt, this isn't my first rodeo. ;-)
Stay tuned for Part 2 of my Guestzilla series "The Drunk Guest."