To me it depends on what I've written so far, I like to keep things simple but sometimes a long title works fine.
I think about the story and what it is about, I have a story about witches and in that story witches come from a valley, so "In The Valley of Witches"
With individiual chapter names I have less of a problem with "bad titles" as they are just minor titles, but often the same thing applies, what happens in the chapter or what is a word/sentence that represents the chapter.