There's only one reason most casual fans knew Bill O'Brien before he was hired at Penn State: He was the guy that got into a sideline screaming match with Patriots quarterback Tom Brady.
Never a head coach on any level, never a subject for public scrutiny, O'Brien was essentially an anonymous assistant until that argument went viral (nearly 100,000 views on YouTube).
O'Brien, of course, has since made a name for himself. As for the temper? The former New England offensive coordinator hasn't lashed out at Penn State quarterback Matt McGloin (yet, at least) but we have seen the 43-year-old show some fire on the sideline.
Most of his anger has been directed toward referees. Several times this season, O'Brien has argued calls with Big Ten officials, sometimes stomping onto the field, other times slamming his headset to the ground.
On Wednesday, O'Brien was asked about his thoughts on Big Ten officiating. The issue was in focus after the Nittany Lions' 35-23 loss to Ohio State last weekend when several calls -- including a bizarre call for defensive holding on a punt -- had O'Brien fuming yet again.
O'Brien tackled the question diplomatically. He prefaced his answer with a disclaimer.
"I want to make sure that people know I have a ton of respect for the Big Ten referees and Bill Carollo, the head of referees," he said.
However, O'Brien has a few qualms. He said after the season, when he gets together with Big Ten officials, he will ask to have a few things clarified: "what is this, what is that, what are we looking for here?"
After Saturday's game, O'Brien was asked if he was given an explanation on the holding call on the defensive punt. O'Brien's response was two words: "Um, no."
On Wednesday, O'Brien conceeded that as a first-year head coach, he probably hasn't been the easiest to deal with.
"I'm sure they haven't had a lot of fun with me," O'Brien said, offering a smile.
He said he respects referees immensely and thinks they have done a good job communicating for the most part. What it comes down to, O'Brien said, is standing up for his team.
"I'm going to fight for my staff and for Penn State and that's the way I'm always going to be," O'Brien said.
Hard to imagine how O'Brien would have been if he were still in the NFL when replacement referees were running the show.