The only part of the first Michael Bay movie that I enjoyed was the Scorponok fight against the army in the desert. I gave the 2nd movie a chance, but found it to be even worse, with the addition of racial stereotype transformers. I completely lost interest in the series at that point and skipped the 3rd movie. When I saw the first reveal trailer for the 4th movie (Age of Extinction), it actually piqued my interest somewhat. But that interest was completely dashed when I later saw this movie poster:
Optimus Prime riding Grimlock like a horse? Consider my childhood memories of G1 Transformers raped. So, I skipped that movie as well, and had no interest in The Last Knight either.
I will admit that the Bumblebee movie piqued my interest again, but it was mainly because of the scenes on Cybertron. I worried that would be a very small portion of the film, so I didn't make a serious effort to get to a theater while it was playing. I'll probably stream it at some point. I don't get how the mainline Transformers movies banked so much money.