One is with Apple ID infrastructure, one with Image Capture in Snow Leopard, and a third probably arose in an iTunes server during an iOS tunes purchase.
Two of these bugs defeated Apple 2nd tier support. All of them are likely rare; I will probably never see these particular bugs again. Unfortunately, there are a lot of these bugs arising from interactions of Cloud and software and data.
One bug I've definitely solved -- it was bizarre. I have a good theory and a test case for another. The third might be fixed but needs more testing.
It's mildly satisfying to figure these things out, but it's an insane waste of time and neurons. I could have been learned options trading  in the time I've wasted.
Note that only one of these was OS X specific. Two of them are Apple Cloud bugs. The ones I understand best appear to be complexity problems -- too many moving parts, too many edge cases, too many ways for things to break.
Post-singularity life does not scale.
 Yeah, there are no good investments any more.
Update: This Stross essay is pertinent.
... We're living in the frickin' 21st century. Killer robot drones are assassinating people in the hills of Afghanistan. Our civilisation has been invaded and conquered by the hive intelligences of multinational corporations, directed by the new aristocracy of the 0.1%. There are space probes in orbit around Saturn and en route to Pluto. Surgeons are carrying out face transplants. I have more computing power and data storage in my office than probably the entire world had in 1980...
... to the extent that mainstream literary fiction is about the perfect microscopic anatomization of everyday mundane life, a true and accurate mainstream literary novel today ought to read like a masterpiece of cyberpunk dystopian SF...Even dystopian science fiction didn't predict we'd spend all our time keeping our whizzy tools working.