Crowds at WWE live events have been growing more and more unpredictable in recent years.

As part of an evolution rooted in the company’s popular “attitude era” of the 1990s, professional wrestling fans have taken to intermittently ignoring the best intentions of behind-the-scenes puppetmasters and -- gasp! -- occasionally exhibiting minds of their own.

Today, nearly two decades after crowds first started chanting “die Rocky die!” because they resented the way a 24-year-old golden boy named Dwayne Johnson was being foisted down their throats by promoters, it’s fairly commonplace (bordering on clichéd) for wrestling fans to cheer certain “bad” guys while booing certain “good” characters.

According to the WWE company line, this is part of what makes said audience so great, though it’s easy to imagine wrestling’s army of showrunners and writers secretly find it irritating.

In any case, that unpredictable nature might have raised serious questions about how the so-called “WWE universe” would react to Brock Lesnar on Monday night, as he returned to the fold and stepped through the literal/metaphorical curtain for the first time since 2004.

After all, wrestling fans viciously taunted Lesnar on his way out the door eight years ago, chanting “you sold out!” and “this match sucks!” during his tiff with Bill Goldberg at Wrestlemania 20 because they already knew both guys were departing WWE immediately after: Goldberg to become an occasional color commentator at small-time MMA shows; Lesnar to make a failed try at playing in the NFL.

In the intervening years, Brock didn’t have many tremendously nice things to say about pro-wrestling, speaking out against what he called the "WWE lifestyle" and telling Maxim Magazine in 2009, "You get so brainwashed ... the guys who get out are the smart ones, really and truly.”

If his four-year UFC career did anything for him, it established his credibility as a legitimate tough guy only while simultaneously undermining it. Lesnar garnered quick and arguably unparalleled success in the Octagon, but eventually proved unable to hang with MMA’s elite heavyweights, suffering embarrassing losses to Cain Velasquez and Alistair Overeem and twice seeing his path interrupted by reportedly life-threatening bouts with diverticulitis.

Lesnar additionally used his time in the UFC to reveal himself as a personality who is not easy to cheer. For the duration of his MMA career he was surly and boorish; mocking his opponents, needling fans and acting by turns aloof and hostile toward the media. Though his crossover fame instantly made him the UFC’s biggest pay-per-view draw, many MMA fans never quite warmed up to him.

Despite failing against the likes of Cain Velasquez, Brock Lesnar was welcomed with open arms upon his WWE return. Josh Hedges/Zuffa LLC/Getty Images

Contrary to the mainstream stereotype, pro wrestling fans are smart enough to know all this. They understand both that Lesnar acted like a jerk throughout his UFC tenure and that he ultimately couldn't cut it at the sport's highest level. Frankly, there was no telling how the wrestling faithful would react to that knowledge as a noticeably smaller, slightly doughier and far, far less tanned version of Lesnar showed his face during the final segment of “Monday Night Raw” this week.

Answer: They love the guy, maybe now more than ever.

Lesnar was given a hero’s welcome back to the world of professional wrestling. WWE fans -- given time to lick their wounds after Lesnar spurned them years ago -- appear to be more forgiving than their MMA counterparts.

In truth, the company stacked the deck in Lesnar’s favor during his return by having him hit the ring and deliver his old school finishing move to John Cena, who is currently the good guy fans love to hate for his squeaky-clean image and status as a true company man.

Even amid a shifting landscape where WWE appears at times to be scrambling to keep up with the increasingly discriminating palate of its fan base and at times unapologetically obdurate in the face of it, one equation still worked like a charm: Pretty much anybody can get cheers by doing something bad to Cena.

Still, watching Lesnar slam Cena with his signature “F-5” facebuster, then prop himself up on the second rope to soak in the cheers, it was instantly clear that the big fella is back where he belongs now.

His flights of fancy with football and mixed martial arts are mercifully finished. They were always somewhat awkward fits, anyway. With his unique blend of size and natural athleticism, Lesnar could have been great at nearly any physical endeavor, but what he chose first upon graduation from the University of Minnesota in 2000 was professional wrestling.

It’s the one thing he’s been consistently great at for more than a few fleeting years. Now he’s back to it and, while it’s impossible to predict how wrestling fans will react to him over the long term, it’s good to see "The Next Big Thing" once again in his natural habitat.