It's absolutely insane how much difference your (and your team's) attitude makes... Not exclusive to Overwatch of course, but like any team game where each player is so significant it decides games time and time again...
Recently I've been trying to focus on learning to ignore and deal with raging/salty players better, and it makes a huge difference. It's not just about avoiding getting tilted yourself by someone having a go at you, but also avoiding making a situation that doesn't involve you worse (props to the missus here, who is clearly leagues ahead of me in terms of general social awareness, and pointed much of this out)
Here's an example... was playing in a game the other night, right out the gate after picking heroes, a guy on our team pipes up "omfg, widow, rly?" then "gg then, I guess you want to lose"... The guy playing widow didn't say anything or react in any way, but having a player on our team being so hostile before the match had even started was irritating to me, so I said something like "you know what's a great way to get people to do what you want? yelling at them like a jerk"... In my mind I thought what I said wasn't particularly hostile; I was sticking up for my fellow team mate, trying to bring some perspective and justice to the game, putting this guy in his place, what a hero!
The guy's reaction was to completely lose it and go off on one for the rest of the match (now directed at me)... he said "now I will make us lose because of your ****-talking" and proceeded to intentionally sabotage any chances we had. End result - we lost (of course), everyone's time wasted, I was even more annoyed than I was to begin with (and it probably spilled over to the next game where I'd have played worse as well). The labored point I'm trying to make here is not to get drawn into these things, whether it's directed at you or not. If I'd just said nothing our widow player might have turned out to be competent and the other guy might have just gotten on with it as well (maybe we'd have won, who knows)