Here is how you know you will throw a match
When you tell your fed jungler or AP carry "hey, their ADC is fed and ours only has 1 kill. You need to use your early edge (13/2/2 or something) to push objectives and not just chase kills.
The response "relax I'm just messing around, we got this". 100 percent for sure knew we were going to lose.
Its amazing how stupid people can be.