I was getting some weird errors when using a Neo ObjectContext on a Web as a global variable. This thing is supposed to be dependency-injected into factories and stuff, but I've set it to be a static property long time ago and saved me a lot of effort, since most stuff became possible with the Neo code generation tool.
This was long before I learned that singletons are evil.
Anyway, I've been getting very weird errors. Such as, I see a page with a record that should have been deleted, I refresh the page and it's not there, I refresh it again and it's there etc. It looked as if there were two contexts, and the record has been deleted from only one of them. However, since a Context was a static variable, there couldn't possibly be two contexts, right?
Or so I thought. Recently, I've been investigating the whole remoting thing in connection with Ivonna, and I discovered the trivial fact that different static variables exist in different AppDomains. So, I thought that maybe there are two AppDomains for the same site? A quick experiment showed that this is true indeed, if there are two (almost) simultaneous requests.
And the moral of the story is.. dunno, will figure out tomorrow.