I had extremely high suspicion that you are talking about OW as well but since you didn't mentioned it, i didnt want to sound as if i'm derailing your thread. not the first time i link the post to another thread.
i've had some close games, BUT we still Lost. 0 ! or Draw ! and that sucks!
in csgo, sometimes our team mate is doing bad in terms of kill ratio = they're like 0 kills 7 deaths, but nobody is toxic over it or salty. serious!
and that's great. we're still trying.
but in OW, its different, its over pride and stubbornness, also the lack of comm.
in csgo, u definitely need comm, or you just flat out die, i think the same goes for OW but less and less people understand the severity of it.
but as you play the game,
you can understand why you lose, --
1\ sometimes, you just need a rein, even Unit Lost/Stylosa pointed out in diamond rank too, that many people dont play rein. they feel its a boring character, i've taken the initiative to learn and play rein decently tho not my main.
2\ character counters - your team is trying but EITHER your team characters do not counter enemy well OR your team is being Countered. winston or zarya vs genji / dva
3\ either support / tank / dps is not doing their role well
this is very subjective, but you can see, if healing is too poor, then u have to find out why, is mercy healing just 1 person, or are they dying too often, from enemy dps or their carelessness / is tank doing his solo debut / OR is your team following the tanks. dps think of flanking all the time, they go solo without the tank in front, its not flanking, its solo.
4\ DPS is not targeting the right characters, theyre not Supposed to be spamming enemy tanks all the time ! that's what tanks are supposed to be! sometimes DPS needs to guard support, sometimes DPS need to target enemy medics. The idea is DPS/Tank/Support to defend each other simultaneously, so they become invincible.
5\ characters in your team do not suit the map well. i play Mei quite decent but i realized and for all characters, you cannot lockdown a single one. Mei is good in Kings Row for example, and checkpoint maps Nepal but not all 3 of nepal maps too.
so you and your team will need to choose characters right for the map. or Roadhog for attack payload - i still believe that Roadhog isnt for attack in the higher ranks.
6\ this is the hardest one, whole team composition, if the entire team is good for jumping/surprising attack -- the synchronisity of the entire team, this is hard because when you start game with strangers, its hard to know what or which character are they good at. if the team is good at divers, say pharah, dva, winston, tracer/reaper, then you need mercy + zen/ ana. I just do Sub, by picking last hoping others play well.
7\ Blunders - for example, team all over the place or overextending. if a checkpoint map, don't fight enemy in front of their spawn thinking u can fall back, NO. stay in checkpoint and spam enemy entering in. It is too risky for tanks to go upfront and if tanks isnt with others, its split . unless you're someone like genji or pharah who can dodge back quick but its still a very, very bad habit that i dont like, that gives the enemy the advantage.
surely someone dies out there alone, and the team goes snowballing down. it really gets me Boiling when you say on mic to come back and they don't, and ...... they die. sometimes 2 or 3. they die. Thenbing bing bing, checkpoint goes to enemy.
8\ although the team is together, they're not attacking the right method - take numbani as an example, the left upper stairs. when all the enemy camps there, with symmetra and her turrets, if you die there, don't try it again, by dying at the same place again and again.
9\ This one really is a blunder..
team is dead, regroup, wait. don't go too far to the battle zone. too often, team is dead and they go out 2 by 2 and keep dying. sometimes 5 are out there but even 1 more is so important for the team, Mei for example, who can build wall and strongly assist. this is soo important when you're suppose to regroup, and you see some dps trying to flank solo.
10\ proper ultimate usage
in higher ranking games, you need to combo ult to win. the worst is you're by yourself and you try to use your ult. say a Reaper's blossom. Yes, you are behind enemy lines, but even if you ult without your team around, you'll just get shutdown. you can't blossom enemy tank that easily. or they dont use the ult at all, saving it for a glorious play of the game. No, that isn't how to contribute.
11\ which i haven't solved, how do you convince your team to change if any of the above isn't right. you try to say something and they dont listen. they want to hanzo on attack, i dont mind but if theyre bad at it, time to change before its too late. more than often its too late.