Pro Wrestling around the world varies according to perception and style, and wrestlers who work in multiple countries tend to adapt their style to the local brand. It also varies with time. In America, during television's infancy in the 1950s, wrestling matches were mostly just wrestling and if they weren't it involved mostly punching. In the 1980s, it began to be considered an addictive, but cheesy soap opera. In the 1990s, talking, entrances and promos greatly outpaced matches themselves, which also tended to have even more brawling and use of weapons than actual wrestling. At its lowest points worst, American wrestling is treated as a sideshow, at times, literally for concerts and such. Big time wrestling (read: WWE and TNA) has become increasingly scripted, with emphasis on storyline and "high spots" (big stunts and signature moves). Terminology too, as calling a pro wrestling angle a "storyline" would be considered an insult prior to 1989.
In Chris Jericho's book, he mentioned a case of this during a WWE tour in Tokyo. The people behind the scenes were horrified at how quiet the audience was, thinking the crowd was dead and weren't enjoying the show. Jericho (who worked extensively in Japan before joining WWE) tried to explain how the Japanese take a more academic approach to wrestling, analyzing the match quietly rather than simply watching it and cheering. He mentioned how the brass were still uneasy about it and still piped in crowd noise for the TV broadcast. This isn't limited to wrestling, either, see the real life section of Japanese Politeness.
In the 1950s, wrestling matches were commonly won by moves that modern viewers would find incredibly boring, such as the Head Vice, the Abdominal Stretch, and the Airplane Spin. One wrestling gimmick on the recent MTV series Wrestling Society Xlampshaded this: Matt Classic (better known as Colt Cabana) who'd been in suspended animation for five decades and used all three of the above moves as his finishers.
John "Bradshaw" Layfield ran afoul of this while performing at a WWE show in Germany in 2004. He jokingly made a Nazi salute (arm pointed diagonally forward with palm rigid), then goose-step marched down the ring apron. In the United States it's just bog standard Cheap Heat; in Germany, it's illegal (see more at No Swastikas). WWE came under fire for this incident, and they promptly disciplined Bradshaw by.... booking him to win the WWE Championship at The Great American Bash. On the other hand, Bradshaw did legitimately lose a job he had as a TV stock analyst over the incident.
It can be pretty offensive watching WWE's heel Divas go about their slutty antics. But older or conservative viewers are liable to get a dissonant feeling while watching face Divas behave the exact same way. Candice Michelle was particularly guilty of this: even as a face, she would sometimes plant a pseudo-lesbian kiss on other face Divas such as Torrie Wilson, deeply troubling some viewers while inevitably delighting others. Mickie James's Psycho Lesbian also almost completely failed to get over anyway that wasn't positive, as she was never booed for an extended amount of time despite quickly dropping all her previous sympathetic traits.
Up until the 1980s, it was taboo for a man to even so much as threaten a woman, be she a fan, a wrestler or a valet. While comedian Andy Kaufman once had an act where he would wrestle a woman, the objective was never to injure the woman; this was more for showmanship and to sell his act to a male audience. The changes came in the late 1980s, when Miss Elizabeth – the valet (and real-life wife) of Randy Savage – was shoved by the Honky Tonk Man, had her wrist and ankle broken by various heels, was slapped by Jake Roberts (after being made to beg for Savage's well-being), had her name sullied by Bad News Brown, and was constantly threatened, all to the outrage of the face-leaning announcers; at one time, André the Giant grabbed Elizabeth's hair and was planning to brutally injure her, but Roberts — several years before he himself slapped Elizabeth — stopped the whole thing. While Elizabeth was a face, the face-leaning announcers would invariably cheer when the heel Sensational Sherri was knocked around, usually by the Ultimate Warrior[!]. At the same time, heelish announcer Jesse Ventura condemned Sherri being beaten up but blamed Elizabeth when she was in danger. (Even Bobby Heenan, during "Tuesday in Texas," was shocked when Roberts slapped Elizabeth, sure that a DDT was coming.)
During the late 1990s and early 2000s, it was common to see men beating up women. "Stone Cold" Steve Austin was known to give "stunners" to multiple women, including Stephanie McMahon Linda McMahon, Chyna and Stacy Keibler, all to loud cheers of the audience. But when both Kurt Angle and Umaga brutally beat super-hot WWE diva Maria during two different matches, and later, when the 7-foot-3 Great Khali began choking the life and shaking like a rag doll super-sexy diva Ashley Massaro to the point where she began bleeding from the mouth, the fans were outraged. Between this and their attempt to clean up the product post-Chris Benoit led to all man-on-woman violence being banned.
Mocked during Jeff Jarrett's heel phase in the late '90s, where he became outrageously sexist and kept shouting at women to literally Stay in the Kitchen, "barefoot and pregnant." It eventually led to a Crowning Moment Of Awesome when the entire female roster ran out and kicked his ass.
A well-known incident happened between Jimmy Snuka and Roddy Piper during one of the latter's "Piper's Pit" segments, where Piper tried to make Snuka "feel at home" by offering him coconuts and bananas (Snuka, born James Reiher, is of mixed Melanesian and European descent) and calling him a "monkey." It's been referenced many times over the years to the point where the WWE can now comfortably parody it without causing any offense.
The big issue in recent years has been the furor over unprotected chairshots. Knowing what we know now, any new fans to professional wrestling will probably wince when they go back to look at hardcore matches from the WWF's Attitude Era or, God forbid, ECW. (ironically, the wrestlers in much more violent promotions that proceeded them such as FMW and W*ING, still knew to protect their heads and nobody thought less of Kanemura for it)
Conversely, many fans of the Attitude Era find today's wrestling to be embarrassingly unrealistic and stopped watching it for this reason. Back then the suspension of disbelief was fine as long as you imagined that, like boxing, they WERE hitting each other hard and it just didn't look like it. These days, punches land about 6 inches away from the opponent and somehow still knock them down.
Certain tactics during matches today would earn a DQ from the ref while during the Attitude Era or Ruthless Aggression Era they would only get a small warning. As such, older fans may find these tactics weak finishes to a match. Examples include:
A manager attacking a wrestler during a match today is enough to get a DQ while in the past they would either get a warning or ejected from the match.
Physically touching the referee at all.
Attacking your opponent after the match (resulting in a "reversed decision" if the heel was the victor, which is just silly).
Back in the old days, throwing another wrestler over the top rope was an automatic DQ. WCW actually made an angle out of it, when main eventer Lex Luger threw midcarder Buff Bagwell over the top rope - and Bagwell immediately demanded his win via DQ. He got it, and the rule was afterwards officially removed from the rulebook due to being antiquated.
What made this rule particularly absurd is that it's going to happen every time anyway whenever a wrestler gets clotheslined against the ropes, unless he/she "skins the cat."
During the "NWA invasion" angle in the then-WWF, this was among the rules that were in effect in an NWA title match which were known as "NWA Rules." Another one of those rules was that going up on the top turnbuckle would initiate a five-count where afterwards one would be disqualified if the competitor did not come back down.
'Badass' characters in wrestling are often seen drinking beer as part of their gimmick ("Stone Cold" Steve Austin, the APA, and The Sandman spring to mind). This is because in the US drinking is supposed to be an 'adult' thing and the young audience will assume this indicates the character is rebellious. However, said wrestler is usually drinking Budweiser, which to people in the UK is considered quite a weak beer and would have very little effect on one's personality. This would certainly not be enough to turn you into the fighting machine writers would have you believe it does. Coupled with the fact that many people in the UK (and Europe) start drinking at home when they are around 13 or 14, the overall effect is of the character trying too hard to be cool.
This gimmick might not work anymore in the US either, since a wrestler well known for never drinking alcohol is CM Punk, and he is incredibly cool.
Really, the Attitude Era in general (roughly 1998 to 2001) compared to today's WWE, which is still edgy but comes nowhere near the gleeful subversiveness of the Attitude years. Satanic rituals, race angles (including D-Generation X coming out in Blackface), heels (or even faces!) hitting womenon purpose and getting cheered for it, etc.
Which makes sense, considering that everything on television these days has to be politically correct, especially since WWE has been funding Linda McMahon's senate campaign and is thus trying to pretend that the more... offensive bits of the Attitude Era never happened.
One of the worst side effects of the Attitude Era was how almost EVERYONE got turned into a Draco in Leather Pants, and you had to be truly evil, despicable or, in the case of Jarrett, physically incapable of getting over in the first place, not to become "cool."
Vince McMahon is a fairly hardcore conservative, and whenever a feud even touches politics (which, admittedly, happens only rarely), he books the conservative as the face. Problem is, his target audience has shifted left politically since the 80s and now skews fairly liberal (being primarily middle-class Americans ages 15 to 25), which makes things put things like this in-ring debate on the Iraq war seem, well, silly.
Somewhat subverted with Jack Swagger's heel run, which took popular conservative idealogies and turned them into cartoonishly exaggerated villainous versions. However to some people, he and Zeb were right. See also, JBL's 2004 feud with Eddie Guerrero.
Foreign wrestlers (or American wrestlers billed as foreigners) are usually booked as the heels, and nationality was usually played up as part of the gimmick until very recently. Villainous nationalities included German, Russian, Japanese, and - somewhat ironically, as the best technical wrestlers in the world have come from there - Canadian, particularly French-Canadian. However, when these characters would wrestle before crowds in their homelands (or supposed homelands), they would as often as not be booked to win the match, and gain wild applause from the audience despite still being heels! (Jerry Lawler referred to these incidents as "Bizarro World.")
In America, working stiff or No-Selling your opponents offence is considered extremely unprofessional unless done for a good reason, e.g. to build up some "hardcore" credit or put someone over as a monster, and is to be done only with your opponent's consent and/or instructions from management. In Japan, where wrestlers have a more relaxed schedule and more time to recover between matches, working stiff is not only allowed but encouraged by many promotions, and many wrestling schools teach students not to sell for anyone who isn't legitimately beating them up. This can lead to problems when wrestlers trained in one country cross over to the other.
Once during his tenure in the WWF, Jim Cornette shot a promo bemoaning both the WWF and WCW tendencies towards "sports entertainment" rather than actual wrestling. He promised to bring in actual wrestlers to show what wrestling really is. This led to the "NWA Invasion" angle.
Going back even to the 90s, Kayfabe was still heavily enforced. For example the cast of GLOW had to stay in character whenever they were out in public - and that Faces and Heels couldn't be seen together. Professional wrestling these days tends to acknowledge that the wrestlers are only playing characters on TV. It's more unusual to find a wrestler doing an interview in character (One notable exception to this, though, is Twitter, as many Superstars will use their Twitter accounts to extend their feuds and characters beyond what they can in their limited TV time. See Fandango and Summer Rae playing up their Kayfabe breakup for an example.)
The Curtain Call Incident where the members of the Kliq broke Kayfabe at a house show to hug (before two members went off to WCW) resulted in Triple H getting punished. These days the attitude is that house shows are Canon Discontinuity and something only counts if it happens on TV. It's not uncommon for workers to wrestle in a different role (as in a face works heel) if WWE wants to test them for a potential turn - or if they don't have anyone else to work with.
Malia Hosaka was intended to be brought in as a Rocky Balboa underdog from the crowd to challenge Ivory for the Women's Championship. They dropped the angle when people recognized Hosaka from a couple of WCW appearances. Not likely to happen these days when it's virtually impossible for any indie wrestler to be completely unknown.
Masks used to be incredibly common in the American wrestling and still are in Latin American Wrestling, especially Mexico thanks to the legendary careers of The Masked Marvel, The Blue Demon, El Santo, Atlantis, Mascarita Sagrada, Místico etc, the ever popular mask vs mask wager and The Reveal that follows. In America though, masks fell out of favor in the so called "Rock N' Wrestling Era" when wrestling was crossing over with other forms of media such as movies and cartoons, leaving wrestlers to think masks would hamper their marketing value even though they never stopped Mexicans from getting movies or comics. However, with the rise of the internet, masks started making a small comeback in the 50 states as they were one of the surefire ways to force a gap between professional and private life, helping keep the mystique of The Gimmick. Kaiju Big Battel and Chikara in particular ran with this.