I originally created several topics for this website to classify various types of Science. These included Science, Mad Science and Bad Science. Today, while browsing I found that an excellent Bad Science webpage already existed. While I normally think of bad science as pseudo science, they prefer to actually clarify genuine mistakes that are propagated in science textbooks and lore. They include nice sections on Bad Astronomy, Bad Chemistry, and Bad Meteorology. Worth reading!
It includes the excellent quotation
Be very, very careful what you put into that head,
because you will never, ever get it out.
Thomas Cardinal Wolsey (1471-1530)