Very few people are able to get away with being endearing after 1) showing constant signs of incompetence or 2) revealing themselves to be far less equipped for a specific job than they originally let on. This is why it’s extremely important to be attractive (which isn’t that much of a challenge as only generally unattractive people are forced to work in the office setting) so as to be able to bat your eyelashes and giggle whenever you make a grave error, usually one that amounts to a huge waste of paper.
However, as with most things, lack of novelty tends to ruin a tried and true method for success relied upon for too long. Ergo when your “oops…I did it again” look isn’t cute anymore, it’s extremely important to have a contingency plan for how to sustain your ability to avoid a comeuppance or the collective ire of those in the workplace who give more of a shit than you do.
Some alternative options to the “oops…I did it again” countenance of cuteness can be misdirection (“I think Donna took those files downstairs already”–when in truth there is no one named Donna and you have no idea where the files are), throwing your arms in the air and delving into some actual Britney-inspired choreography as a distraction or backing away slowly as though you might disappear into the wall. Whatever your technique of choice, just make sure you don’t rely on your adorable little “I fucked up” face for forever.