Until one day we did a survey asking the audience to rank how useful this presentation was. The outcome: people already knew that we were probably very smart, worked with prestigious clients, were unlikely to starve because of lack of financial resources, and were very professional.
The questions the students had were: are you guys human or nerds, do you really have to work 80 hours a week, how on earth can a physics engineer be useful there? These questions you cannot really address on a slide, so we cut the introduction presentation to the minimum (to re-confirm what people already knew), and then switched off the projector and started talking about us as a person, and opening up the discussion for questions.
Preaching to the converted is a waste of time. Instead, use your presentation to address the issues the audience has.