In my twenties I saw many examples around me that created presentation habits I had to unlearn. Professors at university putting a copy of a syllabus page on an overhead projector. Politicians waffling on TV. Senior student organisation leaders giving very poor speeches. Pompous Microsoft Word memos being printed out and distributed in every employee's mailbox. Boring dinner speeches that everyone sat through politely and quietly.
The world is changing and younger generations have videos of TED talks, Steve Jobs product launches, and other presentations to set new reference points. Still it is worth making sure that you are not following bad habits of other people around you, because this is the way you are supposed to give a presentation.