Does being positive win you more games?

Does being positive affect your game?
Does being positive, win more games?

I'd say it really does.
Just a moment ago. I did a YoloQ(with Vi) Match Ranked and had a Sejuani top with Exhaust Ignite. She fed the hell out of the enemy nasus and the team was flaming on her. Even I did. We were thinking she was trolling or something. However, the enemy team lost 1 single teamfight, and started raging at eachother, from there on, it all went downhill for them. They started getting caught, didn't ward enough/at the right places, starting blaming and flaming in all chat. Meanwhile, we were taking objectives as a team even with sejuani, who was really trying to win. She did very well in the teamfights which made up for her horrible laning phase.
We stopped flaming and the only thing that was typed were either: Take blue, go drake, take bot inhib and back or gj, wp, good focus.

We won the game and we were glad with the team afterall.
In post-screen, the whole enemy team asked to report their whole team apart from themselves.

Staying positive even when losing all lanes really helps at teamfights/objectives.

being positive does also mean not dropping bad going games which can still be won

Yup.

Of course it does man ! When you are positive, you can be more focused, do better actions, better farm and never give up. It makes you not flame your mates and it increases chances to win for sure !

I'd say being neutral wins you more games.