No one is prepared to say, "I failed. I am to blame." The reason is pride. No one wants to be wrong.
No one wants to admit they shirked their duty or waited until the last minute and produced an inferior product. The person who was helping them was at fault or the system is unfair.
Some of us aren't cut out for certain jobs. I am red green color blind. It kept me out of the Navy; was that fair? Fair or no; that was the way it was. Was the Navy at fault? No, I just didn't have the genes.
I am average at mathematics (69% SAT). I wanted to be a theoretical physicist (Big Bang Theory sitcom type dude [hopefully without the neuroses]), but my mathematical aptitude was not good enough. I got Cs in calculus. Was it the professor's fault? No. Was it the Teaching Assistant's fault? No. It was my fault.
Sometimes we don't get what we want and we can't do what we want. Wisdom is embracing what we can do well and doing it with all our might as unto the Lord.
For me, that meant changing my college major to Russian language. (My verbal aptitude was 96% SAT) I did well! Surprise, surprise! I went on to seminary and studied OT Hebrew and NT Greek. I learned German and Serbian while connected to Yugoslavia. I don't speak Dutch well, but I have learned a lot of Dutch in Belgium and Holland.
I also moved my area of interest to philosophy and apologetics and have done very well, as they are language related fields.
Some people are great church planters. I am not. Some people have gifts to allow them to be executives. I do not.
We must accept our limitations as God's direction in our lives and MOVE ON! Blaming someone else is a cheap and lazy way to avoid one's own responsibility to use one's talents wisely.