Briefly

 
"“Bitter is better,” a poet friend said to me when I asked him what he thought of Levine’s writing. My friend preferred the harsh early poetry to the later, softer work, which often ends on a note of tender, affirmative irony: “There is a justice/after all, there’s a bright anthem/for the occasion, something/familiar and blue, with words we/all sing, like ‘Time on My Hands.’” Levine would seem to agree. “I find more energy in my earlier work,” he said after learning that he had been made poet laureate. “More dash, more anger.”"

From Philip Levine, Poet of Drudgery, here.

And in his own words in an interview with Mona Simpson, here.