This is the mindset I go into ranked games with. If I lose a game then I need to look at what I need to do better. Of course some games are uncarriable by anyone non-psychic and non-perfect, but keeping this mentality soothes any kind of rage I had for this game. If mid and jungle died to a countergank while I was top, I should have headed down there to help out/clean up. If the enemy mid roamed top and got a kill without a response, I should have been more vigilant with pings/mias/counterganking.
If you play every game with the mentality "I will only lose if I fail to carry my team, and that's MY responsibility", ranked becomes more fun and your ELO will rise much faster
It's never my team's fault, it's my fault. Raging at them will get me nowhere. I need to get better so I can carry harder, and that's the end of it.
EDIT: For the people that think carrying is 1 man army, that's absolutely ridiculous. Carrying means making plays around your map, getting the best environment for your team to succeed, snowballing, and making the right calls. If they ran into a bush and got ganked, I should have warded better, etc
EDIT 2: Score isn't everything. 6/0/0 can mean you only snowballed your lane, 2/2/7 can mean you snowballed other lanes and the team as a whole is stronger.
Also, for the posters saying this is masochistic, they are reading too much into the word "blame". I don't "blame" myself and beat myself up, I look at the game saying "What could I have done better", analyze it, and enact it. Making the mindset that I'm at fault as opposed to my teammates is actually soothing because I can improve what I need to do, I can't improve my teammates (perhaps as the game goes on I can give advice, but I can't guarantee anything. The only guarantee is with myself, so this method makes the game easier to deal with).