Plenty of confusion around monads, at least that was the case last time I checked.

Design patterns are not "just a convention" they are practical solutions to often encountered problems. They are a way of extracting commonly applied, useful solutions and documenting them for reuse. If you go and read a properly documented design pattern I think it's pretty hard to misunderstand what it is, what it's good for, when to apply it, and when maybe don't. But it is definitely possible to misapply them. I'm still living in the shadow of implementing Observer, and then trying to implement undo as an Observer by translating observed events into Commands and placing them on to the undo stack. Messy.