I know these responses are supposed to be rhetorical, but I can't help myself.
Goldfish popularity: Name a fish that can survive in temps as varied as cold as 32F up to 90F, with low dissolved oxygen levels, high levels of ammonia, nitrites and nitrates? That's why they are so popular.
Fake Plants: they are maintenance free; they will not clog your filter, die or be eaten by plant eating fish.
Water Conditioner: It's a fact that most water treatment plants use chemicals to kill bacteria in our water. The levels are low enough so that they are not toxic to humans, but can be toxic to fish. If you are treating a large amount of water, use Seachem Safe (it's the concentrated powder form of Prime and 5 grams treats 450G of Chlorine treated water) and pretty cheap- 8.8lbs of it will cost you less than $100 and will treat 360,000 gallons.
Xellos: If you wanted to do a 1,000G water change every day for a year, it would only cost you only $0.28 per daily water change. If you are doing 40% per week, that's only $1.12 per month to treat your water.
My pet Peaves:
1. Overstocked tanks- the argument that it is the proper way to keep aggressive fish together is ridiculous. JDM = Just Dumb Man
2. A lot of people on here say, "I will upgrade to a larger tank when X fish gets to be X feet long" but no one seems to actually follow through.
3. The idea that fish are treated like commodities instead of pets. You don't see people trading their dogs or cats on the internet, so why do people do it with fish?
4. People that pose questions to see if they can get someone to agree with their thoughts, when even the OP knows (deep down) that they are wrong. i.e.- can I get a Pima, RTC, Aro etc. and keep it in a 240G?