It's a far cry but I'm going to say Wrestlemania Sixteen was the worst Wrestlemania I've seen, and I haven't seen any of them after Wrestlemania Eighteen except for Wrestlemania Twenty-five. Firstly, like many people pointed out, there was no match featuring competition in a "singles match" traditionally. I wouldn't even expect that sort of thing at Extreme Rules.
The opener was not actually too bad of a match for the part of D'Lo Brown but the other people looked and acted horribly. The Hardcore Battle Royal, as Brain pointed out in another thread, showed the wrong person winning, and plus, seemed like a terrible segment of Sunday Night Heat. Steve Blackman was alright teaming with Al Snow but I can not to this day remember who they fought without somebody bringing it up or thinking of it as a statistic. Oh, the opponents were Test and Albert.
The Triangle Ladder Match was pretty decent but that was all it seemed to me, without taking anything away from it. Again, it was not a traditional wrestling match. I think Too Cool and Chyna may have followed next to take on the Radicalz, but neither Dean Malenko nor Perry Saturn seemed excited enough to be there considering it was a first appearance at Wrestlemania for them, and Scott Taylor on the other side was acting hardly any more than a novelty act. Next, the Triple Threat Match for the Intercontinental Championship and for the European Championship, being carried out with one fall for each title was simply overrated. These types rarely seem to deliver and Angle being the "real athlete" he was did not really step up to put on a classic performance, though I was not expecting anything more than technical wrestling, which he, Benoit and Jericho sure finely did deliver.
The divas were not bad to watch, but they did not provide a special "Wrestlemania moment". Then we saw a drugged addict in Jesse James, also known as the Road Dogg, team with some flash in the pan that could not get past the phase of acting like an older gimmick of the "1-2-3 Kid", which I always thought was horrible, taking on the unlikely partners of an overweight Samoan, who had no business being on Wrestlemania this time other than to provide comical entertainment to people acting childish, and Kane who at ninety-nine percent of the time did not show that he cared who the partner was.
Also, the main event may have been the second worst last match on the card of a Wrestlemania of all times, although that disrespect would go to Bam Bam Bigelow and Lawrence Taylor. Mick Foley could barely walk, Paul Wight did not seem motivated enough, and the time after they were eliminated with left a disaster, as again for the second Wrestlemania in a row, the only remaining match on the show featured a big brawl OUTSIDE of the ring. Seriously, this event made Wrestlemania Eleven and Wrestlemania Nine look almost golden.