For sheer unadulterated stupidity this one is hard to beat even though it happened over 20 years ago;
737 operator flying from Guam to Nauru then to Noumea and Sydney. Typhoon brewing up on 737 track Nauru to Noumea abeam of the Santa Cruz islands. The aircraft weather radar had been u/s all the way from Guam (and before that from Hong Kong). Rather than wait at Guam or Nauru for radar spares and technician from Australia or New Zealand, someone decided the flights should continue all the way to Melbourne where spares available. As a frequent passenger with this company I was aware the radar was u/s and wasn't too happy about travelling but business was urgent and I did.
The captain on the Nauru - Noumea - Melbourne legs decided wisely to keep seat belts on through any IMC. We were in IMC and light chop in the last known position of the typhoon astride our track abeam the Santa Cruz islands. Children were running around the cabin and climbing over seat while seat belts were on. Me, down the back knew radar was u/s and was shi...ting blue lights that we would run smack into CB circling the storm centre. I warned one of the local island flight attendants that the children were in danger as we could clobbered any minute as the crew were flying blind. I was curtly told to mind my own business by the idiot female islander and that the captain knew what he was doing. She had no idea about u/s radar because the captain kept it to the cockpit crew only and had decided not to tell his flight attendants. After all, he reasoned, the seat belts were on so what you don't know won't hurt you.
We hit a couple of CB tops without warning and kids flew in all directions but unhurt. In fact they laughed at free flight. The flight attendants sat down with relatives in the cabin and didn't stop the kids from playing up and down the aisle. No one in that 737 knew what monster CB's were ahead unseen. The FA's had absolutely no bloody idea of the potential danger and the captain never informed them. We arrived in Melbourne eventually.
Heard the 737 departed next day with radar still inop due nil spares and flew same route in reverse with CB's still around. Following day it flew Nauru to Nandi, Fiji and back and encountered very severe turb in CB and on arrival at Nauru airport, captain of that flight grounded the aircraft for turbulence inspection. Spares arrived all the way from Australia a couple of days later. Some operators like to keep to schedule regardless of risk... But as I said, it was well over 20 years ago..