She looked innocent.
“Gangway, pegasus out of control, a hex on the pony who thought a pegasus with no spacial awareness would be funnnyyyyoohshi-!”
That was sort of the point.
“I hope you are going to clean that up, miss! Hang on a minute...”
No pony would ever imagine that she could ever quite manage anything with something approaching competence.
“Oh my gosh, I’m so sorry, is everypony alright? I just get so disoriented sometimes while I’m flying that I can’t help but crash. I tried to warn everypony to get out of the way.”
And if even competence was too difficult to imagine, then nopony would ever suspect her of being able to socially manipulate anyone.
“It’s quite alright miss. The Crown will settle everything here, and fix any damage that you may have caused. I must get this letter to Captain Shining Armor immediately. He needs to know about this. It may put the city in great danger.”
And nopony would ever expect her to be able to instigate a series of events almost specifically designed for one particular unicorn to learn something.
“Going down, out of control, all stop all stop dammit wings!”
“Big Mac! Y’all okay?”
“Nnope.”
“Just great. And with Applebuck Season right around the corner, too.”
“Sorry, Applejack, Big Mac.”
Not that it was entirely an act. The best covers never were. She did genuinely have problems with spatial awareness and orientation, and even coordination at times. They just weren’t nearly as bad as she said they were.
“Incoming, mayday mayday mayday, that’s a thundercloud that’s a thundercloud I’m hitting a thunder-clghck.”
“Town Hall! Town Hall is ruined. Applejack competes in rodeos, right?”
“Yes, Mayor Mare, she does.”
But the important thing was keeping that ‘no suspicion’ thing going. If Twilight and friends ever found out, she probably wouldn’t have to fake her next accident. And as long as most of the ponies only knew her as Ditzy ‘Derpy Hooves’ Doo, the mare who had once legally changed her name to ‘Muffins’ for a season, only the one or two ponies in the know would ever be able to connect her with ‘Agent D’. Agent D was the exceedingly competent mare who had made sure, every single time, that the tools to defeat whatever monster were available to those who needed them. The mare who had given every single advantage possible to Equestria wherever possible.
The thing with Twilight Sparkle had been a long-standing contingency of Princess Celestia’s. There was always a chance that whoever the Element of Magic was would seek out the other bearers on their own. And the smaller incidents that she incited for Twilight’s friendship reports had been another one of Celestia’s ideas.
Ditzy Doo was not fond of meddling in other ponies’ lives like that. Agent D, however, got no say in the matter. But perhaps with the handing over of the Equestrian Intelligence Service to Princess Luna, perhaps she would be asked to do less of that, but time would tell.
And Ditzy had to admit, being the silent hero, knowing that all of Twilight’s current accomplishments were in part due to her, she couldn’t help but feel proud of what she had done. And it was kind of fun, too.