A week ago I spent two hours (maybe even three!) implementing email notification of comments.
It didn't take long to hook up the Yii Mail extension and maybe an hour to figure out the logic behind the task, but no matter what I did, it refused to send emails.
For longer than I would admit openly I used the log, the php die command, echo and print - nothing..
I felt more and more incompetent, and nearly gave up on it, when suddenly one line in my configuration caught my eye.