Oh my god, where do I start???

Personal Finance. It's a massive subreddit, but it's filled with misinformation and groupthink which will keep people generally poor forever- think about people who argue it's better to save money than spend money on college tuition. They'll never get ahead in life. Pretty much anyone advocating a frugal lifestyle- they have no idea how finance works at all and they're screwing up their lives left and right.

Used Cars. They're people out there advocating only buying used and always doing repairs yourself- and I've talked to many of them- and they simply cannot understand that if you live in, let's say, Manhattan, that you cannot find a cheap used car within 50 miles and they can't understand that the average person does not have the mechanical understanding (or the free time) to repair their own car. There are people who absolutely have a used car religion! I've tried to explain to a dude in Las Vegas that most of the country can't actually buy a used car for $1500 because we get so much rain that our old cars rust out and he lives in a flukey region where people end up broke, need to sell their cars, and the weather is such that cars last 5 years longer than average, but no... I must be representing the banking system or something...