The Doctor sits at his chair, gleefully polishing off a plate of Eggs Benedict as he watches through his advanced camera systems the expansion and maintenance of his Android Army.
Then- out of no where - an alarm blares, confetti rains from the sky, and a chipper, familiar tune starts to play..
"What--!?" He bellows as he tumbles out of his chair in surprise. "What is the meaning of this!? Is it that Ridiculous Rodent!? Orbot- Cubot! Find the source of this infernally Infuriating melody and PUT A STOP TO IT--!!!"
His two 'trusted' robot companions search frantically around the room - looking under his chair, in the loose paper bin, under the desk-- essentially, no where useful. With an angry bellow, Robotnik slams his fists into his console - forcing a reboot and finally putting an end to the impromptu festivities.
"Can't you two Boltbrains do ANYTHING right! Ugh, just forget it! I'll do it myself! It's probably less effort!"
As his systems come back online he begins work on tracking and isolating the cause. He discovers that it was an automatic behaviour trigged by The Date...but why? How is there yet something he doesn't know about this place? Impossible!
Some more research was in order. Going through records of the area he had ...ahem...liberated and formed the core of his empire around.
"Ahh, I see. It seems the previous ruler of this area of Cyberspace has a birthday on this very day! How interesting...she must have encoded some kind of automatic celebratory response...hmm...to think that you can encode such things into the very environment...this is...this is...!"
He begins to laugh... He laughs loudly, the sound reverberating around the metal room - a hand slapped to his face at the sheer idiocy and ridiculousness of it all!
"Oh, what a shame! What a shame it is! That she's not even here to enjoy this insufferable surprise herself! Oohahahaha! Oh, that DOES make me laugh-- I must admit; her intellect is impressive to pull off such a feat, but that she used it for such a purpose only screams of her naïvete !! Dohohohoho!!"
The day continued on, Robotnik pre-emptively disabling the fireworks show that had scheduled itself for that very night - "As if I need any more disturbances - an egg centric genius such as myself needs his beauty sleep!" - and with that, it was now just like any other day...
The Eggman Empire - as homogenous and single minded as ever. There was no room for celebrations...that weren't about him.