I Despise Every Player Ever Who Refuses to Win
When you have a clear shot of the nexus and someone on the team decides now is the time to farm or push a lane that doesn't need to be pushed. That player is doing nothing to contribute toward the team's victory. They are merely supplying the enemy team with a chance to comeback.
When a win is 100% guaranteed and there is one player on the team that does nothing to help secure it, that is the very definition of griefing and I will report anyone and everyone for it.
If someone decides to fountain dive to try for an unnecessary ace while the team is attacking the nexus.
If someone decides to get another drake while the team is attacking the nexus.
If someone decides to farm jungle or push a lane despite your team attacking the nexus.
Whatever it is they think is more important than taking out the nexus, they should be reported for griefing and intentionally feeding. It should be an offense if it is not already and I certainly will report for it.