If a jungler dives in solo before you can help, then flame. If a jungler appears to be playing a PVE game even though they are post 6, then flame. If a jungler waits until you die and then goes in and dies as well, flame. If a jungler is feeding your lane at all, flame away. There are some bad junglers out there, but to be fair the meta is not jungler friendly right now except for a select few hyper carries.
But I agree with most of what you said. I get so many pings that are just dumb requests that are not going to end well. I was at rift with it at like 15% left and top starts pinging for me to go assist, and then dives in solo and dies. Then begin the flames that I did not come and help....Or I ping that I am on my way to help, and instead of looking at the map the dive immediately instead of timing it for when I am actually entering. Generally I have issues anytime someone is pinging without looking at their maps. My favorite is also when someone dies and pings for me to finish off the 5 health enemy when I am on the other side of the map.
Here are some I would like to add:
If you have fed your lane and they are 3 levels ahead, I am not going near your lane without another lane coming along.
If you have pushed them under the tower the whole game and have no wards on river to watch, I am not ganking.
If it is
or
on top with their ults up and they have out-farmed you heavily, I am not ganking.