As I work on my little Tornado project I occasionally run into things that are packaged for other frameworks, CouchDB, Recaptcha, that kind of thing.  They're the kind of thing that you can write a basic client for in a few hours (less for Recaptcha, of course), but then you realize there's corner cases, little unclear bits in the API, that kind of thing, which you then have to fix in your custom client.

In Java you'd probably never think of writing your own client.  In C++, definitely not.  But Python makes that first 90% so easy it's a temptation to walk down the road-less-traveled.  Problem is, you're responsible for maintaining the tarmac after you pave it.