biggest turnoff for me when interviewing, is someone clearly being fake to pretend the know everything for the job!

Oh and smelling of sawdust

I should say, we had a guy come in for an interview to a Internet Marketing agency I used to work for before going it alone, he was not bad at interviews, you could tell he had a lot of practise: but hte one reason we did not give him the job - he smelt like he had wood shavings in his pockets!