Disappointed MK Dons boss Karl Robinson hopes Gary MacKenzie will learn from his red card in the 2-1 defeat at Charlton.
Defender MacKenzie gave away a penalty and was sent off for pushing his head towards Yann Kermorgant inside the area.
Johnnie Jackson converted the spot-kick and added a second after he was felled by Luke Chadwick before Dean Bowditch grabbed a consolation for the Dons.
Robinson had a slightly different view of the sending-off, but said: "I accept the good, the bad and the ugly about it.
"The player can't head-butt our player. I'm disappointed they missed that but then I can't accept what then happened afterwards. You can't do it and I think he knows.
"I'm so proud of him in a weird way for coming out and accepting his punishment. I'm not proud of what he did, but he will learn from it and if you take the aggression away from Gary you get half the player."