If you're outside [in winter] without a coat, you will get sick
This is not true. Sure, you will be cold as heck, but catching a cold has little to do with cold; the cold temperature can lower your immune system, but that's it. You are actually more likely to catch a cold in a warm classroom; warm populated areas are at the highest risk for catching a virus. However, if you are in Antarctica, you won't catch a cold - you will be very darn cold, but you will not catch a cold.
Leaving a light on costs a lot of money in hydro bills
What parent doesn't use this as an excuse for you to turn lights off when you are done with them? This is also false, as a single light, running for around a full month without being turned off, should cost under $10, depending on the light & cost of electricity. There are almost 800 hours in a month, and parents complain if you leave a light on for an hour [which costs nothing really]. Next time your parents complain, hand them $10, and say, "Here, this should last the month".
Online banking and shopping sites are dangerous
Well, if a site does not start with https:// then it may be dangerous, as it is not a secure connection. However, if the site you are on has an https:// at the start of the link, then it is 100% safe. These sites do not steal credit card details, and no one has ever been able to hack them - ever. Online banking & using credit cards on secure sites is 100% safe, whereas going to your local bank, or buying things at your local stores can be dangerous [bank robberies, muggings, etc.]. So next time they say the internet isn't safe for shopping or banking, you tell them it is 100% safe - not 99.9% safe - 100% safe.
Porn sites give you viruses
This myth amuses me the most. Many parents assume that porn sites are the most dangerous sites and have the most viruses. They are wrong. Porn sites are only dangerous in the sense that the contents may not be suitable for younger viewers; however, as far as viruses go, porn sites are safe like any other site you would visit. Porn companies want money, and they only make money if their sites are safe, and get lots of customers. When you think about it, they are like any site that sells products and/or services. You are more likely to get a virus from a site with free online games.
There are staving children in Africa who aren't lucky to have the food you do
Well, this is partly true for sure. There are many Africans who live in poverty, and cannot afford to eat as much as others in more privileged countries. However, why do parents bring this up? They are encouraging us to over eat, and become obese, just because there are children who under eat, and suffer malnutrition. It doesn't balance anything, and, with all due respect, we can't just mail out the food we don't eat on our plates and send it to starving African children. If your parents use this excuse, tell them to make fewer portions, and then spend the money they save towards a donation to a foundation for children in 3rd world countries.
I hope you have enjoyed my article, and can find it useful in any way, shape or form. Parents have many false ideas in their heads, and it is up to you to counter their false facts with the truth, and make them look like the one in the wrong.