Some speaking sins, like the occasional “ah” or “um”, will not doom your presentation. With good content, you can earn forgiveness from the audience for those sins.
Other speaking sins are so grave that when you commit them, your speech or presentation is certain to fail. This article reveals the seven deadly sins of public speaking.
http://sixminutes.dlugan.com/2009/09/21/7-deadly-sins-public-speaking/