Sometimes I take up the entire time slot allocated to me for my presentation.
Even though I may need to prolong it by adding more details, talking slowly, showing commercials or products or provoking the audience by bringing out multiple dimensions to any particular slide.
I do it because I want to give it back in the same coin to all those who do not bother about how boring their talk can become for some of us in the audience. To all those who once get a chance to be on stage, keep talking our ears off with unnecessary data inspite of the given format of the presentation. To all those who cause a meeting to prolong well into the night because they do not know how to keep time.