When you win your lane but your teammates feed your lane opponent

I initially wrote this in reply to what I didn't realize was a meme thread (Derpy me, I know), so I'm reposting it here because I think it merits some discussion.

The situation described in the topic is rarely ever a one lane screwed up situation.

1. Did you have a ward and did it spot your opponent's route?

2. Did your teammate have a ward and did it spot your opponent's route?

3. How long was your opponent out of lane?

4. What did you do while your opponent was gone? Did you take a tower? Did you also roam?

I see it all the time, top lane being the most frequent offender. Top laner manages a few kills early and his opponent opts to roam. 5 minutes later the opponent has successfully ganked mid and bot, and secured dragon and one tower. Meanwhile the top laner is still farming away without having even taken first tier tower yet, all the while complaining about the feeders on his team, when in reality his team is basically playing a 4v5.

I don't mean to pick on top laners though. Some mid laners and ADCs are often guilty of this too, especially Vayne players.

This isn't to say that you always have to group, even though that's my preferred style personally. But if your opponent is with his team and you're not, you better have some heavy pressure in your lane. Otherwise you're basically a glorified minion.