No matter what you ask him, it’s difficult to get Joe Flacco worked up. This will shock virtually no one who’s watched him play quarterback for the past decade. “Joe Cool” has become his identity, a rallying cry for those who believe he’s at his unflappable best in the most stressful games and a lament for those who question his passion for the most scrutinized job in American sports. But the latter criticism, that he might not care enough, does bring a smile to his face and prompt a spirited response. “There’s a little bit of you that wishes you didn’t care so you could just go out and play and react,” he said. “But listen, this is my life. We all care. I don’t want to say especially me, but I carry a lot of load for the team and how they prepare. A lot of people look at me and say, ‘This is how Joe’s doing it.’ So yeah, I care a ton. This is what I love. And the more I care, the more I think it bleeds into everyone else.” He paused for a moment. “Listen, it doesn’t bother me that much if people feel that way,” he said of his critics. “Because they don’t know.” Actually, Flacco has become rather animated in recent weeks as he tries to lead the Ravens to a seventh playoff appearance in his 10 years as the team’s starting quarterback. On the field, he’s moving with more ease and throwing with more zip than he was early in the season, when he was still recovering from a back injury that kept him sidelined the entire preseason. In the locker room last week, he engaged reporters and teammates in a lively discussion — complete with pantomiming — of what constitutes a catch in the modern NFL.