And then you get out of high school and you start to actually do research and learn the real answer: Primary sources are always better than secondary or tertiary, so use them when you can.

But Wikipedia IS good for finding those primary/secondary sources. And, depending on the topic, wiki is great for getting a quick primer to a subject or to have an example and is often cited in lectures to students who are expected to be old enough to not stop you and say "Teacher! Teacher! You said to never use Wikipedia!"