I sort of like Dave Lamb's sarcasms, except when he's just mean.
The episodes I like most are the ones where the competitors get well on with each other, enjoy their time, really like the food - and the food is good, well-made and beautiful - and give points generously and there are only a couple of points between first and last.
I like least the episodes with... uh.
The purpose of a dinner party is that people enjoy eating together. It's not for you to teach new habits, preferences, opinions, information or anything to your guests. It's not for you to show off. It's not for you to lecture, it's not for anyone to mock the others or the food, or criticise, or shame or... Your job is to do your best to make everyone feel good about themselves, you and the food.
I know Come Dine With Me is a competition, but keep your criticism to the point giving.
In what way will telling the host, for example, that the plates are cold change anything? Is he supposed to take the plates back to kitchen and warm them up? No. You are just showing off and making an ass of yourself. The food won't get warm because you point out it's cold. You will also give an unfair edge to the other competitors as you tell them to watch out with the plates - something they might have missed as well, as most people don't warm up the plates for an informal dinner at their homes. So what you have done is caused unnecessary sorrow for everyone.
One thing that really irks me with people and food is the terrible intolerance people have. I'm not picky, I know what I like and what I don't like. I don't like seafood. It smells and tastes bad, and the consistence is weird. I have eaten seafood, and I will eat it if I ever has to, but I don't like it.
I don't like onions (onions, leek, chives, garlic etc.) In small amounts, correctly made, in right company, these can be really nice, but 90% of time people use too much, wrong and in everything, so it's better to avoid getting disappointed and having to eat stuff that smells and tastes like rusty nails in sweatty woollen socks.
I don't like mushroom, because they taste dirt.
I don't like asparagus, brussel sprouts, saffron, koriander, coffee and several other things, just like I don't like purple, daisies, ladybugs or Hugh Grant. It's a question of preferences, not that I'd be spoiled, immature and whiny.
It really is not your job to "convert" me. Serving me seafood is just as faux pas as serving meat to a vegetarian.
The worst thing you could do as a host of a dinner party is trying to trick your guests to eat things they have expressed they don't like. I would eat shrimp with aioli and say I like it, because I have manners, not because I liked it.
(P.S. You don't know why people don't like certain foods, and it really is none of your business. Show a little tolerance and respect, and set your guests' comfort before your own.)
Now, there are foods many people don't like. Try to choose food most people will be able to eat.
Food people have generally difficulties with:
offal (liver, tribe) and odd cuts, like pig feet
odd animals, like giraffe
food that looks at you. No whole fish or sheep's head.
raw fish and meat
asparagus, okra, brussel sprouts, peppers, spinach, coriander/cilantro, artichokes, eggplant, beets
garlic and other onions
strong cheeses, blue cheese, havarti, limburger
peas and beans
seafood, especially oysters and squid, sea urchin, roe...
(anchovies, sardines, kippers...)
ants, grasshoppers, larvae... insects
fermented food, like kimchi/sauerkraut
grits, polenta, semolina, rice pudding, tapioca
There is plenty of delicious food most people have no problems eating, so there is no need to serve any of this.
If your guest asks for something, see that she gets it, if possible. Don't roll your eyes, if your guest wants to "spoil" her dinner with ketchup or horseradish, it's her dinner, and really none of your business.
See that there is salt and pepper on the table, so that your guests can help themselves. Some people like more salty or spicy food than others. It's not an insult, so if you take it as such, you're an idiot.
There should also be plenty of clean, fresh water.
Also see that there are toothpicks on the table, and if you serve anything that is to be eaten with fingers, have bowls of water so that people can wash their hands.
Also, if you are the host, see that your toilet is in pristine condition and there's plenty of toilet paper, soap and towels.
Don't tell people what is the proper way of cooking, serving or eating. It doesn't matter whether you're the host or a dinner guest. It's not your job to educate people of the proper way of doing anything. It's a dinner party, not a finishing school.
Don't say food looks horrible. Keep it for yourself. Most probably the others can see it too, so no need of pointing out the obvious, and if they don't see it, good for them.
Don't criticise the food in any way. If you cannot say anything good, don't say anything. If you're a guest of a competition dinner, you have the points to express your critique, if not, it's rude to criticise a gift. You don't need to eat anything.
Don't make noises or faces, don't "ew" or "yuk", don't roll your eyes, don't grin.
Don't ever, ever, ever say the food looks, smells or tastes like poo or puke or anything else inedible. Don't even talk about poo, puke or anything else inedible. Do not talk about disgusting things you have eaten or plan to eat, or have heard someone ate, no discussing placentas, insects, rotten food or baby animals. Also, no medical details, no mentioning of surgeries, injuries, childbirth or illnesses. Don't talk about anything that might make anyone feel sick. No talk about frogs, snakes or snails, even though some people find all these things delicacies. Just don't. If anyone starts talking about these things, put a stop to it immediately.
If you find the discussion boring, start a non-boring one yourself.
If one or more of your fellow guests irritate you, let it. It's a question of just a couple of hours. You can keep your mouth shut for a couple of hours. Lashing out on them will not make them less obnoxious. It will only spoil the dinner from others as well, and yours is already ruined.
Dress up nicely. Be clean. Surprisingly people need to be told this. If there's a dress code, follow it. It's there for YOUR comfort just as much as everyone else's.
Bring a gift. Flowers are good. Wine is okay, even though some people don't drink it. Chocolate is okay, even though some people don't eat it. Other food gifts are okay as hostess gift for a dinner party, for example spiced oil or vinegar, an exciting preserve or cookies.
It is also a nice idea to give party favors. It doesn't need to be expensive or advanced. It's just a gesture.
Have some entertainment or party games.