The biggest red flag when I was hiring was the straight A or 4.0 student. They were all proud of their achievements, and figured they could walk right in to any organization they wanted to.
I never hired them. A student with a perfect record tells me they were not challenged in school. They don't know what failure feels like. They don't have the emotional tools to deal with failure. They were probably used to going to their profs when they got a B on a project and ask for extra credit opportunities to bring their grade back to an A. Or, god forbid, they whined and puled to their pahrunts who may intervene on their behalf.
In the real world, there will be failures. Whether you're an engineering organization which fixes complex problems, or part of a sales force, if you cannot demonstrate you've had significant failures and can demonstrate that you've learned something from your failures, then I am not interested.