WWYD if you saw your doppelgänger?

Last night I dipped into the B&N leather-oleum edition of Marvin Kaye's Ghosts: a Treasury of Chilling Tales Old and New, which B&N has titled merely Ghosts. ANYway, I read "Thurlow's Christmas Story," and wondered, as I often do when reading a doppelgänger story, what I would do if I saw mine. I waffle between trying to defy the rumored fate (by fleeing or averting my gaze), accepting it (by dropping dead then & there), and trying to negotiate my way out of it (by speaking to the d.g.). (I wonder if it would be possible to befriend your d.g., and if so would that change anything?)

I think it's a mistake to try and befriend your doppelgänger! Something would definitely go awry!

I'm pretty sure I would flee, but I'd try to do it discreetly so my doppelgänger wouldn't notice...but then later I'd probably become obsessed with it and spy on it constantly.

I think I would do the same. (I loved Poe's story, "A Man of the Crowd," when I first read it as a kid.) The question is, what would I do if I found that my doppelgänger was having a better time than I was? Would I be jealous and try to insert myself into its life?