And the topic was safety briefings
A good strict briefing with safety questions and knowledge of answers with corrections where needed works a treat. Throw in a bit of approachability and humour adds a lot of clout.
A very brief covering of points that really hack off seniors should also work well particularly if followed up on aircraft with those who chose to ignore.
The type of crew who think they are better than others from the start usually prove their inadequacies on board the aircraft as reflected in this site! They generally do not stay long with one airline as they become recognised as problem people and drift from one job to another.
For those who are geniuinely not up to scratch training and and follow up can be given in flight with scope for improvement.