I found this one on Twitter and since it is so timely, I’m sharing it with you. Double negatives are where you use two negative words which generally cancel each other out. Here is a perfect example of that:
Saying “We never won’t” means we will because “we won’t” means we will not do something, but adding “never” means we will never not do something or, less confusingly, we will do it. Granted, this was probably posted by a tween (although they still should know better), but this error totally defeats the purpose of the message.