I like to insert quotes in my writings because it spices things up. But I have learned from bitter experience that one needs to check carefully the sourcing of a quote because some of them, especially well-known ones, are fake in that the alleged authors never actually said them, though in blog posts that are rushed I sometimes forget to practice the required due diligence.
Kali Holloway provides a list of 19 famous quotes whose authors never made them, such as Gandhi’s “Be the change you wish to see in the world” and Abraham Lincoln’s “You can fool all of the people some of the time; you can fool some of the people all of the time; but you can’t fool all of the people all of the time.”
Most of these misattributions are harmless. The quote is worthwhile for its own sake because it pithily or wittily captures the essence of a point and the authorship is largely irrelevant. The writer is often merely trying to avoid claiming originality for the wording or is trying to give the impression of erudition. Sometimes the original author expressed a sentiment roughly along those lines but nowhere close to the popular wording.
But at other times, these mistakes are not insignificant, particularly when the quote and its author are used to add weight an argument. Politicians in the US are especially guilty of this, often attributing to distinguished people in the past positions they never held. If you can claim that one of the Founding Fathers or the Bible said something, your point carries more weight in the US though quoting the Bible is more dangerous since it is easier to check for authenticity.
Arturo Garcia writes that presidential contender Rand Paul has been repeatedly called out for falsely coopting famous figures in support of his stances.
John Oliver says that American politicians do this kind of thing routinely.