When people learn I work in weddings, it's very common for the next question to be about bridezillas.
Well, in the Middle Ages, sailors to exotic lands brought home stories of giant ship-swallowing squid; and while it turned out that giant squid do exist, they're not as big as the stories make them out to be, and they're very, very rare.
When I show up at the bride's house in the morning, she's usually nervous, excited, happy -- and often stressed and already tired. She hasn't had much sleep. Emotions are absolutely running high. But that "stressed" component rarely overpowers the other feelings. Things do go wrong -- it's raining, there's family disagreements, the flowers arrive faded, there's a miscommunication with the hired car company over timing. But the reaction is rarely anger. It's a lot more likely to be, "Ok, this increases my stress level, but let's deal with it."
The secret is to delegate; and you may find that you don't have much choice -- even if you work as a manager and you're used to being the person who solves problems. On your wedding day, your phone goes to your bridesmaid; I've never seen a wedding dress with pockets. Then you're getting hair and makeup, you're getting photographed, you're getting married, people are hugging you, you're taking more photos, and suddenly you're dancing into the reception. You've got your hands full with these things, and you just get swept along for the ride.
But even when I've met bridezillas, like one in a hundred weddings, they're never bridezillas to the photographer and videographer (so that helps), and they don't stay bridezillas. I've seen people shout at their parents or friends during bride prep. So, yes, that happens. But skip forward an hour, and the conclusion of the ceremony is like the clouds parting or the dawn breaking, and all the stress fades away with it.
Mumzillas or dadzillas, though -- they're the ones you've got to watch out for...