It's been a... chaotic week. That can happen in such a big family as the Wayne family, even before you factor in the whole 'secret vigilante crime-fighting' thing. People in and out, everyone has something that needs doing, the occasional temper flare, everybody's busy and stressed and running around trying to balance everything. The crime-fighting side's been chaotic too - Riddler had some big operation that you've all been trying to bust for a week. It finally all came together tonight - and, thankfully, successfully - but suffice to say it's just been one of those weeks.
Which is why it might come as a bit of a surprise that Alfred sought you out once everything settled a bit for the night, with intent to present you with a small cake. Now, that might not be much in and of itself - the man bakes and it's wonderful - but this cake has a candle on it. This is a decorated cake. This is a cake for an occasion.
In the chaos of the past week, something may easily have slipped through the cracks. Maybe everyone forgot to keep track of the dates. You yourself may have forgotten, even - or perhaps you'd just assumed everyone had, decided not to expect anything, and let it slip by. But while everyone else might be prone to forgetting special occasions in the midst of the chaos of life, Alfred would never let someone go uncelebrated.
And so he has baked you a little cake, as one does. "I know it is a bit late in the evening," he acknowledges, placing the plate on the table in front of you, "but I am glad I caught you before you retired to bed."