One of the biggest qualities in a human being is her or his ability to accept his/her mistakes, to be able to say "sorry." As a perfectionist, making mistakes is something I never take lightly, but owning up to my mistakes is something I have always done.
When I deal with people who are not capable of accepting or voicing their mistakes, the feeling I was have is that of frustration and sadness. I once read that it was my ability to desobey and make mistakes that makes a person human and the lack of ownership has always struck me as an exit strategy of the coward.
I believe that a person who can never admit error is locked in a cell created by their own denial.
I never find that taking ownership for errors to be diminishing to a person. To the contrary, it shows maturity and the willingness to grow. It has been in each mistake I made, that I learned a lesson. It has been through my biggest mistakes that I have found a better person within myself.