The often sullen California welterweight showed off his chatty side at a news conference Thursday, wielding the microphone like a talk-show host. Diaz hogged the dais, throwing out comments and interjecting whether there was a question directed his way or not.
It ranged from the poignant to the bizarre.
"(In terms of) craziness, that was a 10 out of 10," UFC president Dana White said afterwards.
At times, Diaz's stream of consciousness monologues seemed to bewilder champion Georges St-Pierre. Other times, a stone-faced GSP seemed antagonized and appalled.
"He's in a different place than he's ever been because he's really mad," White told reporters later.
Normally as cool as a cucumber, St-Pierre (23-2) is jalapeno-hot going into Saturday's main event.
"He told me a few days ago 'I want to make sure when this is over he (Diaz) retires,'" White said after the news conference at the Bell Centre.
"I've never seen Georges like this before a fight," White added. "He's really nasty and short with everybody.
"I got here earlier, they (the fighters) are all in the rooms, I went and said hi to everybody and Georges was weird. Georges just isn't Georges right now. Not even close to being Georges."
There was no handshake after the two fighters posed for photos and they didn't get that close to each other either.
Dressed in a suit jacket with an open shirt, St-Pierre was occasionally amused, more often poker-faced and sometimes upset by Diaz' antics during the 26-minute news conference.
Fellow fighters Carlos (Natural Born Killer) Condit, Jake (The Juggernaut) Ellenberger and Nate (The Great) Marquardt didn't get a single question. Jonny (Bigg Rigg) Hendricks got one.
Instead the casually dressed Diaz held court, reeling off a long line of beefs including his picture on the promotional poster for the fight — evidence, he says, that the UFC likes to portray him as the bad guy.
"The picture of me is like from years ago," he complained. "Can I get one buttered-up Photoshop picture in a magazine or on a poster? I've had plenty of ugly posters. I know they can do better than that but they're not worried about it.
"I hate to play the victim card but I like to think it's not always my fault that I come off the way I do."
He got GSP going after looking directly at the champ and castigating him for saying he reminded him of the bully who used to taunt the champion as a child.
"How many times have you had a gun to your head, Georges? How many times has someone put a gun to your head? How many of your best friends been shot through the chest with a .45? Or how many of your best friends (have) been stomped or put to sleep into a coma?
"We all had to deal with these things in life."
An incredulous St-Pierre looked like someone had just given him a fork and told him to eat the journalist in front of him.
"I'm sure my past doesn't compare to Nick. I don't even know why we're asking this question," he said when a reporter later asked him to respond to Diaz.
"The reason why we're fighting each other is I believe Nick is the best guy right now in mixed martial arts and I'm fighting him because he's the best guy."
That led to another exchange between the two, with Diaz concluding that the UFC was selling "wolf tickets."
A bemused St-Pierre wondered out loud what that meant and he wasn't the only confused one in the room. Condit, apparently either more streetwise or with a better vocabulary, whispered a definition.
Apparently it is bull — a story that has no basis in fact.
White did not disagree later, saying he is in the business of selling fights. But he noted that the UFC didn't make up Diaz's post-UFC 137 comment that St-Pierre wasn't hurt, he was scared. Or that GSP had promised to lay a beatdown on Diaz, calling him the most disrespectful human being he ever met.
It's all music to White's ears.
"People are into fights where people don't like each other," said White. "You get excited for fights like this."
St-Pierre and Diaz also got into it when Diaz recalled how neither would give ground when the two ran into each other at a hotel some time ago.
"You really think I'm afraid of you," said St-Pierre, his voice rising. "Are you crazy in your head, man? I'm not scared of you. You'll see Saturday if I'm scared of you."
One question later, Diaz went back at St-Pierre.
"Why are you mad, bro? Because you're full of (crap) and everyone knows it?"
"I didn't say nothing bad," said GSP. "You started the whole thing."
Diaz did apologize to the fans for skipping Wednesday's public workout, saying he had only got in at midnight the night before and needed his sleep.
"All the other guys flew in before he did," said White, who noted he landed at 4:30 a.m. Thursday. "And what's funny is (manager and head trainer) Cesar Gracie planned his flight, because Cesar said if he goes earlier, he won't show up.
"We don't just throw flights together, we work with the teams. We've never had these issues before but we're dealing with Nick. We know that."
Diaz (27-8-1) has been suspended twice for testing positive for marijuana and almost had the UFC banned from a Las Vegas hospital after he and Joe (Diesel) Riggs brawled in the medical facility where they had been taken for their post-fight checkup following their UFC 57 bout in 2006.
Diaz was also dropped from a UFC 137 title fight with St-Pierre in October 2011 after failing to show up for news conferences in Toronto and Las Vegas.
White said Diaz had not been disciplined for not showing up Wednesday, saying he would rather pick his battles — meaning missing a public workout is pretty much a misdemeanour on Diaz's UFC blotter.
But he also said that in spite of all his missteps, Diaz had done more to promote this fight than he ever has before.
When it was all said and done Thursday, St-Pierre sounded like the one tired of all the tomfoolery.
"It's not fun to be here. I'm cutting weight. We're all cutting weight. We're all in the same boat. We have to (answer) the same question all over again. It's getting old. But it's going to be over soon."
White, for one, knows Diaz could make his life far more complicated.
"Should he win Saturday night, it's going to be interesting," he mused.
"He is a fascinating human being, very tough to figure out," he added. "What most people care about, he does not. He's a very unique individual."
Diaz offered his own self-analysis.
"It's the funniest thing but I like to think I'm not a violent person. I'm a martial artist. And I like to be respected as a high-level martial artist," said Diaz.