Totally agree with this. Unfortunately, we won't see this until they start working. There are great interviewees (I had 2 people recently who came with glowing resume and experience and looked excellent during interview - both ended up not working after couple of months because they had horrible attitude and work ethic) and there are also "fit" factor that is subjective. You can say the same things to different hiring managers and get different responses that could end up getting a job or not.
Back to the original question: that's why internship is useful to stand out during the recruiting process: you have your degree, but your ex-boss(es) will be the one(s) who can provide further insights about your character, work ethics and people skills. Got my first job in the US here because I interned for 3 months in regional accounting firm in WDM. My former boss (blessed his soul in heaven) vouched my character and work ethic to the hiring manager and that made the difference.
Agreed. We tell all our intern candidates that the internship is a 3 month interview, both for the company and for the student.