Michael Bay is only an atrocity if you expect him to be Martin Scorsese. He has said multiple times that he enjoys making action flicks for teenagers. He doesn't pretend to be a lofty director with lofty aspirations, so he cannot fail at said goal. However, I will agree that some of his Transformers movies (namely 2 and 4) really push the envelope for uninspired media--but then again, he's probably fully aware of this. Also, he must have really low standards for script writers on a lot of his films.
To agree with you though--Pain and Gain was easily his best movie. I think it was very very solid.