I know you're going to be careful about insulting and arguing from the other responses in the thread. There are a couple common behaviors that the IFS flags as aggravating a situation that aren't as well known that are easy to avoid once you know about them.
Don't call for reports.
Don't inform someone that you're reporting or muting them.
Don't link someone's KDA or CS.
Don't call trolls trolls or inters inters.
One report is enough. The system runs a review for any report. More don't do anything.
Reporting or muting are private decisions. A muted person that wants your attention may resort to trolling. A person who knows they're being reported already may feel like there isn't a reason to keep under control (the minimum that they had) because they're already being reported.
People already know their cs and KDA, the only reason to bring it up is to rub their face in how poorly they're doing. (If you're trying to help them play safer, use future tense language to make a plan of action, like: "farm cs in the top lane until you have another item". The IFS flags criticism, but not plans.)
If a troll is trolling or an inter is inting, they already know it and are doing it to get a response out of you. Responding to them publicly gives them what they want. If a person is playing poorly, and they're tilting then criticism of this sort can break their will. If a person is csing poorly, they're already getting frustrated that they're csing poorly. Frustration leads to more mistakes. If someone keeps getting caught out and killed, they may get frustrated and try to earn back the deficit by playing even more aggressively. That'll easily lead to feeding the enemy more. Insults won't help, and can even lead many to actually inting.
Also, if a person is just not good at the game, insulting them won't make them any better. If it's ranked, eventually they'll derank. Everyone also has off games. Some more than others, but as long as anyone can have a good game where they do better than normal, anyone can have a bad game where they perform worse than normal. Insulting people because their performance has a bell curve distribution doesn't make sense, because the criticism can't change anything.
