Have you got a cautionary tale to share?

Sometimes, something which is in some way bad, happens to you, or you hear of something happening to someone else, and you want to warn others, so they will be prepared and know what to do, if it happens to them.
This certainly applies to scams, but I have a more unusual cautionary tale to share. It is not something people would easily talk about - but others might really benefit by hearing about it. The father of someone I know had prostate cancer and one morning he could not urinate. His wife phoned the doctor’s surgery , who told her a doctor would ring her later. She rang and rang again and still no call from the doctor, so finally she took him to A&E. By the time they got there he was in terrible distress, and had kidney damage.
I do not know how many GP surgeries - if any - can do what a man who cannot urinate urgently needs done. But if they cannot help they should tell anyone in this situation to go straight to A&E, or maybe urgently call for a District Nurse. But do not wait. Act at once.
What other cautionary tales have others to share ?