LW2: You sound like a real winner. You "wouldn't allow" her to have her wedding when she wanted to have it, instead of saying "Hey sis, much as I'd love to be a bridesmaid, that weekend isn't good. You might want to find someone else." Then you lectured your sister when she complained about the flowers (granted, I can't think of anything I'd care about less than pretty but dying flowers at a wedding, but that was unnecessary). You could have just sympathized. Then you refuse to video the wedding and call her marriage "doomed"? Even I, who hate weddings and would only be involved in one as a guest, think you were really pretty nasty. I would apologize and be a sport and video her wedding and stop with the unnecessary criticism.