I've been through periods when I could enjoy things that are so bad they're good. I have a borderline morbid appreciation for the absurd. I'm a sucker for spectacle. Really, I should have been able to find something of worth in the Transformers movie. Instead, I feel like a worse person for having seen it.
My take is that they were trying to avoid what happened with Superman Returns. That was one of the most expensive movie ever made and it virtually failed in theaters. It was kind of weird and people didn't get it. To avoid that fate, they made this the most bland, inoffensive, banal abomination they could.
The movie seemed to be written by a bunch of different people who weren't in communication with one another. None of them seemed to agree on what kind of movie it was supposed to be.
The special effects could have been the saving grace - they clearly spent a lot of time, money and effort on them - instead, they made it worse. The design was so bad, you could never tell what was happening on the screen. It was a mess of vaguely metallic shapes spinning around with slack-jawed actors trying to look scared in front of a green screen.
The worst thing I can imagine, though, is that negative reviews won't effectively communicate the worthlessness and might actually compel people, out of curiosity, to spend money on this piece of shit.