I watched a little further on Kurt's video; it's pretty clear from his body language that the Nose's antics are eating away at whatever passes for friendship on the internet. Kurt very graciously keeps saying "I love ya, buddy, but..." before eviscerating him.
And Nick's pure laziness returning messages has got to be infuriating. He calls or regards these people as friends (at least outwardly), but can't be bothered to put in anything more of an afterthought's worth of effort when trying to get in touch.