the story: Data records a letter detailing, among other things, the wedding of Miles and Keiko O'Brien.
similar to: "In Theory" (Next Generation), "Explorers" (Deep Space Nine), "Dear Doctor" (Enterprise)
my thoughts: Groundbreaking without being overly significant, "Data's Day" is one of those episodes you can heartily recommend to fans of the series. It's a true slice-of-life experience.
"In Theory" later in the season revisits observing what being Data means on a routine basis, and on the whole it's fairly mundane, though not in a particularly trivial way. Data's wonder at life around him, and his attempts to make sense of it, has a wide range of implications. He's the only character who could get away with having nothing to do with someone else's marriage and yet still be relevant to its occasion.
It's not particularly a surprise, however, that this isn't an experience the franchise rushed to duplicate, and thankfully when it did there was usually a better point to be made, some personal achievement (the Siskos bonding in "Explorers") or perspective worth noting (Phlox's opposition to Archer's actions in "Dear Doctor").
What's puzzling is that Data is composing a letter to Maddox, a character we originally meet in "The Measure of a Man," and he's supposed to be addressing matters of his own unique nature. If the recipient had been anyone else, or merely his recording a common log entry, it would have made more sense.
As much as you might enjoy Data in the episode, it's much more important as an O'Brien story, the culmination to that point in his whole development, and his further adventures in Deep Space Nine, solidifying him as important in his own right, and not just as a familiar face.
It's always nice to have a change of pace, and aside from everything else, this is an episode that proves once and for all that Next Generation is comfortable in its own skin.
Colm Meaney (O'Brien)
Rosalind Chao (Keiko)