One of the things that really gets me down in my current job is having to work with IIS, ASP and the many godawful COM objects you have to shell out for to get basic jobs done (upload files, email, manipulate images, anything more advanced than very simple cgi and database access in fact).
After doing a load of work on some mod_perl stuff ( deploying a wicked fast front end to a huge system with an ASP backend ) it is so unpleasent to return to ASP hacking - no useful error messages, no errorlog that I can just tail, having to re-register components and restart the server (that has a hundred odd sites on it).