Win Lane; Lose Game
Literally, this is the biggest problem with this game. I'm so tired of winning my lane, then every other lane feeding to the point that I can't carry the game. Sure, I have no problem with others losing their lanes. Feeding is a choice. My philosophy is that there is no reason to feed. You can lose lane miserably, but you have to have made a conscious decision to feed. If I'm losing lane, I'm going to build defensive items because that's what they're there for. It's not fair to me, or the rest of the team that you're itemizing improperly. Every game is a new game. The same build you continue to build won't always work. You have to adapt to the situation.
TL;DR It is your conscious decision to feed. You can win a losing lane by itemizing correctly. Don't feed to the point that your other teammates can't carry you.