If you don't like weddings on your birthday...don't go to a wedding on your birthday. Simple, really. Or did you expect them to move it, so it didn't clash ?
My younger sister's wedding was a bit painful. The husband was Polish-German, and his family had a massive chip on their shoulder about it. Someone massively upset her by asking if her throwing coins at on the train of the bride was a Polish thing. She completely lost it and told everyone it was typically German, to the bemusement of the (mostly German) attendees, who knew nothing about it. A quick text to my Polish colleague in the UK revealed this was a typical backwater Polish thing.
She deliberately excluded myself and my partner from almost every photo - no idea why. The bride threw a massive freddy fit because she didn't have the bridal crown for the photos necessitating my dad making a 2 hour round trip to pick it up. For the evening meal, "Battleaxe", as we had come to term her, was supervising the serving of the food, much to the bemusement of the venue staff, mainly, it seemed, to exclude certain people from getting certain food. We, strangely, passed muster, although she cancelled coffee and cake for everyone (even though it had been paid for) as she wanted to leave. One of the groom's brothers was banished to the outer reaches of the venue, because he had married a (real) Pole, and more importantly, a Catholic.
My aunt then threw a fainting fit - I took it seriously until my Dad said it was because she wasn't the centre of attention and was upset her husband had refused to attend, as had grandma because she hated the groom.
Notwithstanding all of this, we actually had a nice time and the hotel was lovely.