But on a more serious note, I've always enjoyed the detail and realism of his work, how there's so much color (and such rich textured colors) even in people going about their daily life. THere's a touch of beauty about the mundane, somehow. A personal favorite: El Geografo [The Geographer].
On a personal note, there's a chance I've seen this one in person. I have a vague memory of one a lot like it, and according to Wikipedia it's on display at the Stadelsches Kunstinstitut in Frankfort. I've been to a few art museums in that city, but it's been more than a decade, so I can't remember the names or work out the precise timeline. Still, the possible connection is a neat one for me!