Well, no of course you don't and I'm sorry for the annoying title (I expect that sort of tithe irks loads of people in itself!)
Anyway - I hate it in a novel where a character sees or hears or experiences something, and everyone he/she knows (and the character him/herself sometimes) tries to explain it away as being stressed or tired or overworked, so that their mind or eyes are playing tricks on them.
I've spent the last 20 odd years being tired and stressed, and I haven't yet imagined that I saw Mary (for example) in the Co-op, only for my dh to say "you can't have, she died ten years ago. You're tired, you must've conjured her up because you're overwrought and you used to buy those pizzas there for her", and for me to respond with "oh yes love, of course you're right, I imagined the whole thing". I'm more likely to look at him and say "don't be daft, I saw her"
I'm willing to accept there are certain conditions (perhaps involving gin) in which I might think I've seen something or someone I didn't. But I can't imagine resurrecting Mary in the Co-op because I'm stressed. It seems such a lazy device to use in books to explain (or attempt to explain) something away.
Am I being very stupid and this sort of thing does happen frequently? Willing to be corrected!