I can't recall a more childish, petulant debate performance than what Democrat Paul Sadler delivered in the first general election debate between the Democrat and Republican Ted Cruz. 

Here's the first part.  Right off the bat Sadler has his panties in a bunch.  For the most pathetic display of Sadler's disposition fast forward to the 16:48 mark.

But I did like the debate format (but the moderators took no control over the situation).  It provided for an actual exchange between the two candidates.  Let them hang themselves - and Sadler certainly did.  This is a far cry from the debate setup we'll get with the presidential candidates.