I lose game when teammates are bad and win games when enemy is bad

I'm sorry to say but that does actually say something about yourself. A good KDA is irrelevant if you aren't helping your team and this is a team game. Sure, having team mates who lose lane hard does happen and it can be frustrating but that doesn't mean a loss. I've carried plenty of games even on supp where my team mates feed simply by talking. I'll encourage them when they do well and tell them what to do, where to go, etc. To win, all you have to do is work with your team. I get the feeling that you're the type to rage in chat when teammates do poorly.

What does that say about you?

That mean you suck when ahead or plat allot of early game champion and don't close the game out fast