If you ever catch yourself messing around with jQuery and are trying to make JSONP calls using .getJSON(), just remember that since you’re (probably) making a cross-domain request, the .error() handler is not thrown. Which means, if you have any control over the uri that is being called, DON’T name the response “Error” when there’s a problem as you’ll never see it.

I was making this call:
$.getJSON('//remotedomain.com/api/?x=' + someInput + '&callback=?', function(data){…}

and the execution was skipping right over the code in that block, given a response from the server of:
'[{"Error": "Some problem happened"}]'

In the end, the solution was to change the error message from the server from saying “Error” to something else, e.g.:
'[{"Problem": "Some problem happened"}]'

Hope that helps someone out and saves them the 2 hours I just lost. Though I guess I did learn something new!

[Note: this refers to jQuery 1.7.2]