Although, looking back at the Markdown spec it explicitly calls out that inline emphasis should be supported, so un*frigging*believable should be unfriggingbelievable…which all the Markdown parsers seem to support.
Yet, all of them also do not support un_frigging_believable, it comes out un_frigging_believable, even though the spec says * and _ are interchangeable. 
Markdown. Am I right?
The parsers also do not treat inline ** bold the same as italics.