I absolutely loath them, especially family weddings.
I don't drink (I mean, a glass of wine here or there, but I'm not really A Drinker, so an open bar doesn't mean much to me) and I don't dance... it's one thing if it's a friends' wedding and I'm hanging out with my gang of friends trash talking on how crappy the wedding is, but for family weddings (eg: cousins, friends of the family, etc), I show up, give my gift, say hello to the bride/groom, and bolt out the back door as soon as possible.
I think the worst was my neighbor's wedding... he and I are friends and I'm cool with most of his friends as well, but everyone I knew at the wedding was in the wedding party so I was stuck in a room where I knew no one sitting around a table with a bunch of geriatrics. making it even worse was the fact that I agreed to give 3 members of the wedding party a ride home afterward, so I was basically forced to stay for the entire duration of the reception.