In what proves to be a nice little device, "Data's Day" employs the conceit of Data writing a letter to Bruce Maddox (the guy who put Data's rights on trial in "The Measure of a Man") in order to supply us a first-person narration and a "day in the life" approach to observing everyone's favorite android. Data does not sleep, so the episode appropriately begins not with him waking up, but with him running the bridge's night shift just before everyone else clocks in.
The story's approach is structurally refreshing — and because it involves Data's bafflement over human emotions, it has an amusing whimsy. Sure, we've seen most of this before, but this time we get to experience more of it from Data's point of view. The story thrusts him into the middle of the upcoming wedding of Keiko and Miles O'Brien, and when Keiko has cold feet, she unwisely uses Data as the conduit for communicating this information to Miles. Unaware of the emotional fallout of a wedding being called off, Data delivers the message to Miles as if it's good news. Not a hilarious joke, but a whimsically effective one. Data's bafflement is offset by those, like Geordi, who take human nature for granted; Geordi assures Data that the wedding, inevitably, will go forward.
Worth the price of admission is a scene where Crusher teaches Data how to tap dance, which reveals the disparity between his technical abilities and his social understanding. He can match step for step the most complicated tap-dancing moves, but is at a loss as to where to look and when to smile while slow-dancing.
Amid the lighter elements is a mysterious plot involving Vulcan Ambassador T'Pel (Sierra Pecheur) and a rendezvous with a Romulan warbird onto which she is to beam for negotiations. When T'Pel is apparently killed in a transporter accident, it's Data's natural ability for logic that is able to discover that she was not, and that she's actually a Romulan spy returning home with information. (The ensuing standoff, for once, ends with the Enterprise retreating with empty hands.) While this more meaty plot seems at odds with the story's lighter tone, in the context of Data's observations and narration, it works. "Data's Day" is not groundbreaking, but it is pleasant.