When Sun Kil Moon's Mark Kozelek isn't telling his audience to "shut the fuck up", he's throwing similar insults at The War on Drugs.

During his set at the Ottawa Folk Festival, Kozelek wasn't too impressed with the sound of The War on Drugs' main stage set bleeding through to his: "Who the fuck is that?" asked Kozelek. When the audience told him who it was, he replied with "I hate that beer commercial lead-guitar shit." He also introduced a song with similar levels of humour, "This next song is called 'The War on Drugs Can Suck My Fucking Dick'".

This is what The War on Drugs had to say about it:

The war on The War on Drugs.