Phil's relationship with Clint varies depending on the verse, but they're always very close. In the main verse (where Clint is my Clint), Phil and Clint are like brothers. In other verses, like the one with @prplhawk, the two are romantically involved.
Whatever the nature of their relationship though, Phil always has reason to blame Clint for his grey hairs.
One of the most infamous times Clint gave Phil grey hairs was the time he brought home the target he was supposed to kill--the Black Widow, Natasha Romanoff.
Phil was very upset with Clint for that, because the archer acted without giving him a heads up or even much of an explanation for why he disobeyed orders.
Phil may have been a bit hostile and distrustful of Natasha for longer than necessary in part because of his hurt feelings over Clint's actions, which was very unfair of him.
At least he believed her when she claimed to have been shot by the Winter Soldier in Odesa.
Speaking of the Winter Soldier, Phil was utterly unsurprised to find out Clint had been involved with bringing him in and breaking him free of his programming. In fact that had been something of a running joke between him and Clint after Odesa, that Clint would bring him in like he did Natasha.
