Some quotes are attributed to the wrong person. Some get their words garbled a little. And others were just made up and we don't know where they really came from. However, many of these misquotes are versions that I've never heard. Does anyone really think it's "Bubble, Bubble, toil and trouble"? After all, the next line uses "bubble" as the rhyme. Who are all these people getting quotes so very wrong? John Green sets the record straight for mental_floss.
There's a line attributed to Carl Jung: "Superstition and accident manifest the will of God." For a few weeks, I've been trying to track it back to Jung's corpus, but I can find it in only secondary sources. Very frustrating. It may be a false attribution.