Alternative Character Interpretation: The series was pretty much built on this. Any one of the five main characters can be viewed in a positive or negative way, depending on which side you choose to take.
Is Ray a hardworking, basically good guy whose bitch of a wife won't give him a break, or a lazy Jerkass who won't lift a finger to help at home?
Is Debra a bitch hypocrite who doesn't appreciate the nice life Ray has built for her, or a put-upon housewife who gets no help from anybody?
Is Marie a controlling, manipulative old maid, or a passionate matriarch who means well for her family?
Is Ray really the favorite or does Marie just think he's too weak to function on his own? Does she dismiss Robert's success as a cop because she's so worried for his safety? Or is he simply a pawn in her manipulations?
Is Frank an ignorant, unappreciative asshole who is emotionally abusive to his wife and kids, or a family man who made them a damn good life and did better than his physically abusive father and grandfather?
Is Robert a good guy who can't catch a break, or a perpetual complainer who dug his own rut?
This was part of the original genius of the show. It was a groundbreaking idea at the time not to designate a hero, but rather to leave it up for interpretation and let the fans choose whose side they were on. This in turn generated a wide fanbase of all different kinds of people who liked different characters for different reasons. Most Dom Coms and sitcoms in general have followed in this path since, making it harder to realize now why ELR was so wildly popular back in the day.
Debra. To people who can identify with her, she's a beleaguered, long-suffering heroine with the patience of a saint. But to her detractors, she's a hypocritical Smug Snake and Karma Houdini. To most, she's somewhere in between.
Raymond in later seasons, as he became much more callous, as well as spineless when it came to choosing between Debra and Marie.
Marie is one herself. Some find her to be superior to Debra as she cares more for Raymond's well-being, others find her to be too meddling and self-centered to be likable.
Broken Base: Depending on who you ask, "Bad Moon Rising" is either the best episode in the series or the worst episode in the series. The same could also be said for "Marie's Sculpture" and "The Faux Pas," albeit to a lesser extent.
Designated Villain: Jerry Musso in "Somebody Hates Raymond". While definitely arrogant, he nonetheless doesn't even dislike Ray personally; the former just doesn't find the latter's work entertaining, something which falls under freedom of opinion instead of anything actually evil, and he simply loses patience with Ray nagging him about the reason for his disliking. Furthermore, Musso has every right to decide who's allowed to guest-host his show and who's not. Nevertheless, the episode seemingly vilifies him as someone so bad that even Robert, himself at odds with Ray throughout most of the episode, is ultimately appalled enough to give him a "The Reason You Suck" Speech for Ray's sake (granted, it is awesome and heartwarming at the same time, though).
Freud Was Right: Used in "Marie's Sculpture" with Marie's...rather "feminine" abstract statue.
Marie:Oh my God, I'm a lesbian.
Funny Aneurysm: In one episode, there is a rather unpleasant scene where Ray tells Debra that he found out that their daughter Ally has been bullying another girl on the school bus. Debra shrugs it off, saying she doesn't think it's a big deal and that it's just kids being kids. When Ray asserts that bullying is indeed a big deal and notes that he and Robert are still scarred from their own experiences, Debra smirks and calls him a wuss, and then starts calling Ray names while the studio audience laughs, this scene is considerably less funny today due to the rash of bullying-related suicides and murders over the past few years.
One episode revealed that Debra (and Marie) would tell their kids to think less of their fathers and covertly try to make themselves as the more adored and likeable parent. The episode treats this as a sneaky but wacky act on Debra's part (she pokes fun at Ray's inability to tell when she's gotten a new haircut, or how he's not always zipped up), but more serious on Marie's part (she derided Frank and told her young son how she couldn't understand how anyone can live with him). In real life, this is called Parental Alienation Syndrome, and is found in many mean-spirited and bitter divorces.
Growing the Beard: The early episodes of the show weren't bad, but the characters hadn't been fully realized yet, which meant the show was originally kind of generic, and even kind of slowly paced. However, once the show and characters found it's footing (around the end of season 1, beginning of season 2) the show became memorable, relatable and pretty consistently well written.
Harsher in Hindsight: When Robert comments on how he doesn't picture Frank outliving Marie. Peter Boyle died shortly after the series ended, with Doris Roberts surviving him by a whole decade.
Left Back deals with the issue of Michael being held back a year and being separated from Geoffrey. In 2015, the actor who played Geoffrey killed himself, leaving his twin brother and co-star alone and grieving.
Informed Wrongness: Ray in some episodes of the later seasons is portrayed as being wrong no matter what, whether or not it actually makes sense. Even in episodes where Debra does the exact same thing or does something worse, Ray will inevitably be the one forced to apologize and/or the one who gets humiliated at the end of the episode.
For all the instances of IW on this show, "Ray's Ring" has to be the worst example. Ray was simply minding his own business in the airport when the lady hit on him, and he promptly turned her down when she did. Of course, Debra acted as though he threw the ring away on purpose and welcomed the advances of the woman.
It's Popular, Now It Sucks: Initially, the sitcom was highly-touted by critics as a great new show that wasn't as popular as it deserved to be. Once the ratings started growing and the show became huge, the series was now considered an easy target for people mocking "modern sitcoms".
Ray as well. Not only does Debra become harder to live with as the series progresses, but Marie's smothering really screwed him up. For just two examples, he mentions having nightmares about a "crazy tree lady" who followed him to school (which Robert reveals was Marie), and she held him back a year in pre-school just because she liked their walks to it. And consequently, he is a lazy, whiny, immatureMama's Boy.
Debra, to an extent. Admittedly, part of her frustration can be traced to living opposite Raymond's parents, who drive almost everybody crazy with their intrusiveness. Unfortunately, she chooses to take it out on Raymond, who doesn't exactly care much for this setup either.
Ron the Death Eater: Ray for some people, particularly those who are actually married, Debra for those who are not.
Seinfeld Is Unfunny: The idea of having a sitcom that focused on the parents instead of the kids was a revolutionary idea at the time, which helped this show stand out. Nowadays, a lot more sitcoms focus on the adults than the kids.
Squick: From "Whose Side Are You On?", when Marie compares Ray to Frank:
Marie: "This is a good husband! Anytime you wanna trade places just say the word. I mean, if I was forty years younger and he wasn't my son-"
Ray: "Okay ma!"
Strawman Has a Point: As the seasons went on, Ray generally morphed into the show's main strawman. A lot of times the show would seemingly attempt to paint Ray's opinion as the "wrong" one, even though Ray often did have a good point.
Unintentionally Unsympathetic: Debra. Marie's criticisms of her can be incredibly venomous and nasty at times, to the point where we should be able to sympathise with Debra — but her own Jerkassery towards Ray often mitigates that.
Values Dissonance: The show made a big deal out of Robert living with his parents into his forties. Thanks to the 2008 recession, which we're still feeling to an extent today, the idea of someone living with their parents to save money doesn't seem so odd.
The Woobie: Robert as the show's resident Butt Monkey. Constantly made fun of by Ray and Frank, neglected by Marie as a child, divorced, and constantly trying and failing to get away from his parents. Perhaps the hardest episode to watch for a Robert fan is the one where Marie, Judy, Stephania and Amy force him to sit down and listen as they discuss every single character flaw they can think of, even if they aren't actually flaws and are just things about him they personally dislike.