When asking for directions, people who don't have the vaguest idea where the place is but insist on telling you, usually for ages, that they don't know, "but it might be near <add random road/shop/pub>"
Trying to be helpful is nice, but please just say "Sorry, I haven't a clue" and move on...
I got asked where a restaurant was ; hadn't a clue and said so only to get rebuked by the questioner who insisted if I was a local I should know ! So under force suggested where it might be (it wasn't).