On a recent holiday overseas I rented a villa. One toilet cistern was
taking hours to refill after a flush. After a few days it wasn't
filling at all so we abandoned using it. (there was another).
A few weeks later I enquired of the owner if it had been fixed and was
told that the plumber had to replace the cistern because it had been
worn out due to people constantly trying to flush it.
I guess that replacing it also replaced the flexible pipe which was
probably blocked so the job was a success!
What amazes me is that some people are so gullible and accept
(immovably) what they have been told.

Any other examples?