I failed a class, once, at community college - it seriesly wasn't my fault. Mostly. It was partly online and the professor didn't bother to actually get the assignments to the ones of us who took it just online... a 1-credit waste of time class. I should have protested but I was 16 and stupid.
Fortunately it didn't prevent me from getting into grad school!
Oh I believe any class you failed wasn't your fault. I was goofing off, and hated the class. History is a weak point for me. I like historical context and historical ideas, but I am lousy with names and dates, which makes me particularly weak on history tests ;~D