Is there a wrong way to use a library?

“And these children that you spit on as they try to change their worlds are immune to your consultations”
—David Bowie

I have vague memories of getting points taken off on my math homework for not showing my work, and even worse, being marked down for coming up with the right answer, but doing so by not using the proper method. More recently, in the early days of the web, I recall struggling to write code up to spec that also rendered properly in browsers with a variety of quirks. Dare I use the <table> tag for non-tabular data, for example.