Hama had a critically acclaimed/commercially successful run on Wolverine that Harras abruptly ended, removing him from the book so that he could put a rotating team of big name writers (notably Warren Ellis, Chris Claremont, and Erik Larson) on the book.
As a consolation prize (since Hama was popular with the editorial staff), Harras gave Hama Generation X to write. Hama was livid and HATED Generation X and went out of his way to scorch earth the title, explicitly writing garbage stories that were designed to get it canceled, culminating in Hama ignoring EVERYTHING Scott Lobdell had set up with relations to M and Pennance by saying M was a pair of twins pretending to be one person and Pennance was the "real" M.
This created such a shit storm that Harras confronted Hama, who was unrepentant that he had pissed fans off and turned what was supposed to be a pet project of Hama's into one of the worst selling X-Men books at the time. Hama even told Harras he was trying to get the book canceled, as Hama was so fucking checked out and hated Harras THAT much for taking him off of Wolverine. And that Harras not only fired Hama on the spot but permanently blackballed him from Marvel as a result.