I'm in typical "so much to do, running late" flail mode, so just for fun, here's something I've been playing with for a while, my laws of TV World. These mostly apply to American television, though I have noticed some of these popping up in British shows, as well. Enjoy!
1) Television homes and apartments don't lock from the inside, leaving television characters with no way to keep out annoying, wacky neighbors or nosy family members who barge in all the time. Even if a character lives in a crummy New York apartment (or a "TV crummy" apartment that's supposed to be bad but that's huge and fabulous even for non-New York standards) and has to go through an elaborate ritual of unlocking a dozen different locks to get through the front door, once she's inside the apartment, the door stays unlocked so that her wacky neighbor across the hall can wander in and out. I'm not sure how TV characters avoid being killed in their beds.
2) Television characters hang out around the house -- reading e-mail, watching TV, doing housework -- in their underwear, and they "forget" they're just in their underwear when someone knocks or rings the doorbell. However, this rule is fairly specific and applies primarily to two particular groups:
-- Attractive women who wear cute, matching lingerie sets involving pushup bras. They must be perfectly groomed, with a full Brazilian bikini wax, no leg or underarm stubble, and a full makeup job.
-- Unattractive men with hairy bodies and pot bellies or comically skinny men, wearing baggy boxer shorts and possibly a dirty wife-beater tank top.
In certain circumstances, attractive men might be seen in their underwear, but unattractive women in ugly (comfortable) underwear are not to be seen.
3) Unlike hotel and motel room room doors in the real world that in many places are required by law to automatically lock when they close, hotel and motel doors in the TV world can be easily opened from the outside with no key and with no juggling of the little plastic key card thingy. If two people traveling together have separate rooms, they can easily wander into each other's rooms just by turning the doorknob/handle.
4) Although television homes don't lock from the inside when a character is home (see rule 1), the doors will lock automatically from the inside if a character in her underwear (see rule 2) or less steps outside. Maybe she should wait for the wacky neighbor to come along and let her in, since the door is never locked to the wacky neighbor (see rule 1).
5) Even though, in the real world, most of the time it's the women who tend to be cold (menopause aside) and the men who tend to be hot (at least, according to all the office thermostat wars I've been through), in the TV world, the men usually wear leather jackets or long, flowing coats while the women with them wear skimpy, sleeveless tops.
6) Even though in the real world, most young people are nearsighted rather than farsighted, and therefore need glasses to see at a distance instead of for reading, most TV characters who wear glasses only put them on when they're reading.
7) Even if a TV character does actually need glasses all the time to get around and not just for reading, in a really intense action or romantic situation, he can get around just fine without glasses (and without bumping into things).
8) Women on television have sex while wearing a bra. The bra is usually black, but when the woman dresses to leave and puts on a white shirt, the black bra doesn't show through the white shirt, even when the woman is very fair-skinned. Almost all TV world sexy bras are black, no matter what color the outer garment is, or how sheer it is.
9) People in television small towns speak with southern accents, no matter where the small town is located. The accent gets heavier the more backwards the town is supposed to be. The town may be in far northern Minnesota, above the Arctic Circle in Alaska or the Vermont mountains, but if they're inbred yokels, they'll talk like Arkansas rednecks.
10) Television people develop southern accents when they grow old, even if they aren't actually from the south. This is especially true in science fiction series when the characters age prematurely and rapidly due to some freaky disease or space anomaly, even if the characters normally don't have a southern accent. The heavier the bad old-age makeup is, the heavier the accent.
11) There are three Christian denominations in television religion: Catholic, generic Protestant, and crackpot fundamentalist. The only way to tell them apart is that the crackpot fundamentalist minister or faithful member will have a southern accent. Otherwise, their churches, services and doctrines are more or less the same, and the ministers all wear clerical collars. "Ethnic" Catholics (Italian, Hispanic, Irish, Polish, etc.) are the main exception, with a touch of the culture added to the Catholicism for a sense of Old World mysticism, usually used to show how out of step they are with the modern world, either for sinister or humorous purposes. All clergy or deeply religious people are the most likely suspects of any murder, which is usually committed for judgmental reasons.
12) On television, "science" is an all-around skill. The person who's good with computers can also throw together chemistry formulas, improvise electrical circuits, analyze rocks, run genetic tests, identify dinosaurs from fossil fragments and spot the rare plant whose sap is the antidote to the poison he just identified through spectral analysis. The more specialized and advanced the "science" character's studies are in one area, the more other sciency things the character will be able to do. PhD in physics? Yeah, that DNA sequence will be a piece of cake, right after he's finished doing that autopsy and hacking into the Pentagon.
13) Television world medicine is a lot like TV science -- if you've trained in one area, you can do all of it. Say you specialized in cardiology. That means you can also do brain surgery, plastic surgery and gene therapy. (I'll give them a pass on all doctors being able to deliver babies because med students do all have to do an OB rotation that involves delivering babies.) TV world medicine also has a fast track that allows people to head hospital departments or be the chief medical officer on a military base (or space station) at an age at which they'd still be in medical school or at most still be a resident in the real world. TV doctors also don't necessarily have to have any related training or experience to hold these positions. If you're super-bright, you may get to be a chief medical officer at a military outpost, even if you have no experience in field surgery or working in combat conditions. You can be put in charge of an entire hospital within a couple of years of finishing your residency. Being really smart is all that matters in television medicine. Training and experience are irrelevant.
14) If you're a regular in a TV world coffee shop, bar, or restaurant, you never have to pay for your food or drinks. You just wander in, banter with the owner while eating or drinking, then wander out (or, often, rush out) without money ever changing hands.
15) In TV world, attractive single people are all over the place. A single person can't walk down the street without bumping into one. In fact, if an attractive single person does bump into someone, probably spilling something all over the other person, that person will quite likely be an attractive single person of the opposite sex. New bosses and new employees of any single main character are also likely to be attractive, single members of the opposite sex. Ditto neighbors. In fact, it's practically newsworthy if a single character runs into someone who's unattractive or unavailable. A television single woman never trips on the sidewalk and falls into the arms of someone who reminds her of her grandfather (and if she does, he has an attractive, single grandson he wants to introduce her to). It's always a hot, single guy. If a television single woman runs out into the street and is almost hit by a taxi, the taxi driver will be an attractive, single, available man, as will his passenger and several of the bystanders who rush to help. Exception: the attractive person of the opposite sex might be temporarily unavailable if the angst of the forbidden fruit is part of the plot, but the person will eventually become available.