Dean: When he thought you were going to die, when you got hurt on the job.

Sam: When you guys just had an argument and he left for a few days then came back.

Castiel: When before he left for the civil war in heaven.

Crowley: When he was on demon blood

Charlie: When she went to Oz

Kevin: When he was on Garth's boat and he had a meltdown

Gabriel: When he was in hiding with you