I suppose it's different for the type of job one is seeking but my biggest turnoff in an interview is the person who tries to project as an overly ambitious go getter when there's nothing but fluff on the resume. Don't tell me how you're a workaholic if you haven't worked actual paying jobs throughout your adult life. And please for the love of all that is Holy don't tell me that your greatest weakness is that you have to work on a project until you think it's perfect, especially if your application materials have errors in them. I like a good bs'r as much as anyone but I won't green light anyone I don't trust.