Everyone and his friend is already aware that installing rubygems to a non-default location was a nightmare just until very recently (that is, version 0.9.5, produced on 2007-11-19).
Now, suppose we try to do something simpler, like err... uninstalling a gem. gem remove mygem yields no results. I do gem --help and... there is nothing about removing a gem in the command line help. Fine. Before deleting manually, let's look it up on the internet. RubyGems User Guide says it should be gem uninstall mygem. How nice!