What's Wrong with the Default Alert Rendered by the Browser?

What's wrong, for me, isn't the native alert. It's a personal pet peeve that most of them ask "yes" or "no" questions when "Okay" and "Cancel" are the actual options presented to the user.

Also, I believe localization of the web app's text can be made more difficult when the text's semantics don't align with the native UI's semantics.