Once in a while you stumble upon weird limitations of applications or APIs. The latest one I have seen is a limitation of the Integrated Web Services Server for i (aka AS/400).
When you try to use a web service developed in RPG that uses 8 parameters you get the following exception:
com.ibm.as400.data.PcmlException: Attribute, entrypoint="MYOPERATION", only allowed for programs with 7 or fewer parameters. Processing <program> element "MYOPERATION".
Of course this limitation is documented:
A procedure in an ILE service program (*SRVPGM) that is to be externalized as a Web service operation can have a maximum of 7 parameters.
Come on IBM. Seven parameters? What is this? The 80s?