Bryant yelled at quarterback Tony Romo after a third-down incompletion intended for Dwayne Harris late in the third quarter, a possession that ended with the Cowboys kicking a field goal to push their lead to 13-7.
Bryant also had a shouting match with tight end Jason Witten after the Lions' go-ahead touchdown with 12 seconds remaining, an exchange that was heated enough to prompt inactive defensive end DeMarcus Ware to step in and separate the two.
"My passion is always positive," said Bryant, who had three catches for 72 yards and two touchdowns on six targets in the loss. "It's always positive. It's going to remain the same way. I'm not saying anything wrong. I'm not saying anything bad. It's all positive. That's just what it is.
"I'm the nicest person off the field. When I'm on the field, even when I look angry, it's still all good passion. It's all good passion. I feel like that's what we need. I'm going to remain the same way. I feel like I love this game. I love it. In order to win, you've got to be passionate about this game. You have to be. You've got to let that dog come out and just put it all out there on the line."
Bryant offered no apologies for his animated antics, saying his intense passion is a critical ingredient to giving the Cowboys the best chance to win. He said he isn't concerned if the sideline outbursts look bad to outsiders.
"That's [the media's] problem, because everybody knows up in this locker room who I am," Bryant said. "It's been that way since day one. The day that I got drafted, like I told y'all, don't get it twisted: I love this game. I love my teammates. That's what it is.
"It's going to forever remain the same. It started in Pop Warner, went to middle school, went to high school, went to college, and it's here. It's going to stay that way. It won't change."
Bryant, who wasn't targeted by Romo until the final minute of the first half, appeared to be frustrated with not getting the ball before his first outburst. As he was leaving the field, Bryant ran toward Romo, jumped in the air and made several animated hand gestures while yelling toward the quarterback.
After a brief, emotional conversation with receivers coach Derek Dooley on the sideline in the third quarter, Bryant approached Romo on the bench, nudging Witten out of the way before hollering at the quarterback again. Bryant described the conversation as "just inside stuff" and said it was about the need for the offense to produce points.
"He's never complained to me about getting the ball," Romo said. "He knows that the ball's going where it's supposed to. He knows that.
"When you guys sometimes see emotions from Dez, it's just trying to 'rah, rah' more than it is being a 'me' guy. That's not who Dez is. I think that would be completely out of character for him if there was ever a 'me' situation."
Cowboys coach Jason Garrett echoed Romo's defense of Bryant.
"We want guys who want the football," Garrett said. "Dez has never been a distraction to our football team. He is a really positive asset to our team -- on the field and off. The way he works, his passion for the ballgame; that's good stuff."
The Cowboys scored touchdowns on their next two possessions after the Bryant-Romo confrontation. Bryant celebrated with Terrance Williams after the rookie receiver's 60-yard touchdown catch on Dallas' next series and had a spectacular 50-yard touchdown reception and run on the following possession, breaking a tackle after catching a deep out and sprinting down the sideline.
While defending Bryant, owner/general manager Jerry Jones indicated that the receiver's first emotional outburst might have sparked the Cowboys.
"Not in any way did it concern me," Jones said. "It's not a negative for our team. Matter of fact, when he started that as I saw, timingwise, we started playing better on our offense, and the defense didn't hear it. They were out on the field. It's not an issue.
"I'm not trying to make light of it. But he's a very passionate player, and he competes and works and does all the things that give him the collateral to use with his teammates and with me relative to a few awkward moments on the sideline, overexpression of passion. He's bought enough slack with me."
Bryant acknowledged that Witten confronted him with 12 seconds remaining in an attempt to calm him. That conversation quickly got heated, with Witten shouting back at Bryant and pointing at the clock, but they hugged each other in the locker room after the loss.
"He's emotional," Witten said. "The guy loves to play, loves to win. We were all disappointed it came down to that situation -- they made some plays and we didn't close it out offensively.
"We have a great relationship with him. This is a close-knit group. He has more passion than anyone I've ever played with. That's a good thing to have. With 12 seconds left, we were all upset, but there was still time left. I tried to communicate that. There was more football to play. We were going to get the ball back, and the play we had drawn up, he was a big part of that play. We were trying to get him to calm down because we were going to try to get him the ball on that play."
Witten repeated that he has "no hard feelings" for Bryant.
"I love that kid like a brother," Witten said. "There are no hard feelings. DeMarcus and I talked to him. He's a great receiver and plays his tail off week in and week out. It's as simple as that. It's a disappointing loss. Dez is a guy who plays with his heart. We all do. Those things come up."
The two former Cowboys most associated with the No. 88 jersey, Michael Irvin and Drew Pearson, understood the frustration but said Bryant needs to control his emotions.
"There's no question you got to channel it differently, especially in that part of the football game when everybody is scrambling around trying to figure things out and do what's best to win the football game," said Pearson, a receiver from 1973 to 1983. "At that point, whether it's frustration or begging for the football, which we've all done in critical situations in games on the sidelines. It just wasn't the right time."
Pearson and Irvin said Bryant needs more touches in the offense and felt that he was justified in some ways for complaining given how Detroit's Calvin Johnson was targeted 16 times and caught 14 passes for 329 yards. The Cowboys' Williams, who finished with two catches for 64 yards, was targeted 10 times.
"I had talked with Dez weeks ago and he's in a place where he understands that there are people who want him to win games," said Irvin, a Hall of Fame receiver who wore the No. 88 from 1988 to 1999. "He wants to make plays, and I understand the passion. But for years -- for years -- this is exactly what we complained about. No one on the Cowboys seemed to have any passion.
"Does he need to go about it a little bit better? Me, personally, I've never gone after or will go after my quarterback in any way. When I'm talking to the quarterback, I want him to hear exactly what I'm saying because it's vital for me to get involved. There is never any time I will condone going after the head coach or the quarterback."
ESPNDallas.com's Calvin Watkins contributed to this report.