The author (Ubersmekel of the eponymous Uberpython Pythonblog) dislikes that errors are passed as return values from functions, rather than percolated and caught/handled as exceptions. He or she feels that it is verbose and encourages the missing of maybe-important errors. The author also feels that panic and recover are ill-applied, at least in the standard library. These perceived shortcomings are sufficient not to leave their current language (likely Python, given the blog title).