I had an experience like that today with one of my profs.
I had a test today worth 20% of my final mark. I rarely go to this class, but I always hand in all my work on time and I've never missed a quiz or test. Even still I'm getting 80's in this course. So Today, thinking my class was from 4-5pm I strolled into an empty room only to see my prof marking tests. He looked at me and said "Oh, did you forget about the test?" My reply was "No, actually I studied and everything but due to my miss judgement and not coming to class I thought it was at 4pm. I'm late and it's completely my fault. I really apologize for that." He smiled and actually let me write the test.
My previous judgement of this prof is that he was a bit of an ass. It's amazing how a bit of honesty and taking ownership can really show you someones true colours. I'm a bit embarrassed and frankly ashamed of myself for this judgement. He didn't have any reason to let me write the test. I wasn't there when I should have been, but he did.
I thought I'd share this with everyone, because I frankly didn't deserve to write the test, but was given a second chance.