I found why people call platinum "ego" hell
And it's not what appears to be the commonly cited example that platinum players consider themselves one step from diamond and won't take advice; actually it appears that people can't seem to understand that your team needs your help, because their mechanics ACTAULLY aren't that bad if you give them a chance, most times.
Best example, from anectdotal evidence, is from my time as ADC. I hardly ever get peel or a babysit from even my support to keep me alive when being dove by rengars, renektons, ahris, etc. I ask my team about it, and they simply say i'm bad and they won't peel for me anyway; this creates a cyclical situation where I die because I don't have help, then my team complains I die and refuse to help me.
This is most common from the people who claim they are "carrying" the game, they think they NEED to go in and kill everyone and not think about their team, and while that probably is how they got to plat, it doesn't work against mechanically skilled opponents.
that's just my two cents anyway, feel free to add or not, it was simply a thought.