One of the most frustrating things for a user is to receive a cryptic error message.  This is closely followed by a developer receiving the same error message.  Let’s say you’re using Fluent NHibernate and you get the error message “Sequence contains no elements”.  Chances are, you’ve done something wrong.  The problem is that you’re not going to figure out what unless you actually debug the source code.  This particular error message is generated by the “Single” extension method.  This code by design does the following: Returns the first element in the list ...