The feelings associated in discovering a failure with ones actions are unlikely to stir joy in the average person. It is quite natural if ones desire is to seek something approaching perfection that it is possible that when the outcome, the result falls short of expectation to be disappointed.
As a tester we regularly deliver information of this nature on a regular basis to developers for their own work so it is because of this that the way we communicate that information is so important, to take out notion of blame or fault and rather just explain the results of what was found to them so with as little emotion as possible they can digest this information as objectively as possible and seek to find a resolution to the issue.
The difference though is when one discovers an action of their own that has measured short that there is no immediate separation of fault from actions, especially when one is aware of their own actions, then achieving objectivity is something the tester can only arrive at after the fact.
As someone who prides himself on his work and the quality of what he assists in delivering I would be lying if I did not find such experiences a bitter-sweet experience. Even though moments where a short-coming in my actions have occurred are few and far between, when they do occur it becomes a moment of disappointment as I am immediately aware as to the circumstances of the matter and know it was an area of my responsibility.
Whilst these moments are not ones I seek out they are ones that ultimately prove beneficial. In such situations I have often found myself having been acutely aware of what I had been thinking and what I had or had not been doing at the time when the mistake occurred.
Resultantly and what I believe is the distinction between an average and a good tester is recognising the situation for what it is, an opportunity to analyse what my shortcomings were in that situation and where there is room for improvement and what else I am able to take/learn from the experience. I also value the humility it brings in the reminder of the discovery of one owns short comings, so in short, the whole experience becomes something potentially positive and becomes an opportunity to grow.
So, even though one should never seek to fail, one can still fail to succeed if they let arrogance or ego get the better of them and miss chances like those as an opportunity and something to embrace regardless of any initial feelings associated with it all.