Muliaina became a former All Black yesterday, as a bung shoulder forced him out of the World Cup.
His place at the back will be taken by Israel Dagg who, along with Cory Jane, was disciplined by the team after a late night drinking session last Thursday.
Muliaina said the two players were sorry about what had happened.
"I've been down that track myself. They've found out the hard way ... that is the reality of being an All Black. You are constantly in the eye 24-7. Every decision you make is crucial, not just for yourself but for everyone else," Muliaina said.
"I think Izzy [Dagg] has learnt a big lesson this week, and I'm positive him and CJ [Jane] are going to be better for it."
Muliaina said he now wanted to be an outstanding spectator and support the side.
A CT scan on his left shoulder yesterday showed he had a small fracture in its socket and there was no possibility he could play again in the tournament.
He notched his century of caps against Argentina at Eden Park on Sunday night, but lasted just to halftime.
"I knew straight away that it was pretty bad. I was pretty lucky that it was close to halftime. When I got to halftime the doc had done all the tests and I could not move my arm. So by then I knew something serious had happened," Muliaina said.
The Chiefs captain is off to play in Japan after the tournament so is now as a former All Black.
It was not the way he wanted to go out"This is rugby I think. Last night I was on top of the world playing my 100th game. It is like a roller-coaster ride, really.
You're back down again. Back to reality."
Getting to 100 caps had softened the injury blow a little as had the encouragement from fellow New Zealanders.
"Now for me really it is about being an outstanding spectator for the boys. Hopefully I can be around a little bit longer this week and hopefully next week."
Muliaina played his first test in 2003 and this was his third World Cup.
He said the people around the team would be the biggest thing he would miss.
"I have spent almost a third of my life here. I think the public and people will be missed. I was once told 'what other job do you get to go to where people get up out of their seat and cheer you on, or criticise you'. You don't really get that anywhere. I have been privileged and had a fantastic run, and am a really proud New Zealander."
He said facing the media yesterday meant it had finally sunk in that he was out of the tournament.