Krebs and Dahlin are two of the most fiery/competitive guys on the team. Personally, I'm glad to see this kind of passion in practice. The intensity level has been increased this year -- partly by Ruff, and partly because that's what the boys wanted. They basically said in their exit interviews last year, almost uniformly, that they needed more intensity and to be challenged more. Donny G was a good developmental feel-good coach, but they have a different attitude right now.
Krebs has actually been one of Buffalo's best forwards recently, and he is a known shit-stirrer. Dahlin is as competitive as they come, and he is surely not happy with his first 4 games.
By the way, the comments in this thread about Dahlin and Krebs show complete ignorance about both of these players both on the ice and off. I won't single anyone out, but most of you have no clue what you are talking about. I guarantee Krebs isn't seeking a trade, that he and Dahls are just fine, and that the rest of the team isn't bothered by this incident at all -- if anything, they are probably pleased with the emotion. Dahlin has been one of the emotional leaders of this team for a couple of years already. He will continue that as captain.