The first 1:30 seconds of the game
They are super important, the game isnt sit at your tower for 1:30 if you arent invading. The game doesn't pause for those 1:30 for you to just sit there.
The game isn't listening to your jungle thinking he prattles about how the enemy ivern or nunu or shaco or who ever might gib your red or blue for you to ignore it while they plead for it to be warded at 1:30.
The game isn't watching the enemy with a blitz or naut or thresh or morg or etc in the loading screen only to not watch for an invade. Your trinket isn't a pretty little item that doesn't do anything for the first 3:00 of the game.( just a hint you get a 2nd charge at around 3:30 when junglers start to get ready to gank.)
The jungler really only gets 1:30 of the game where you need to babysit them, after that the jungle's main focus is to help you. So please, I know there have been plenty of junglers who just sit in the jungle and dont gank (or maybe you just think that about junglers just having bad games), but we really do need your help in the pre-minion game. A simple invade, a simple unknowing about the status of our buffs is enough to ruin our early game. There is no exp to miss in lane, no CS to be lost during this time. We need your help for that first 1:30 of the game, after that we will be looking to help you.
So please, use your trinket, save your jungle, and save a life.

I always imagine in the jungler's head,
What could possibly go wrong?
Enemy Triple Kill
, or more specifically, ranged champions with high dps, and you're mostly melees and have to choose between gapclosers and hard CC (or neither! For example
is pretty useless because although his W gives good DPS and his E gives hard CC, his E is a huge commitment and doesn't have huge range rank 1, and he has no damage to follow up on it either) and can't really get both effectively (i.e., two get hard CC, two get gapclosers, the other is ranged, you use your hard CC, your gapclosers go in and get fucked by the 3 enemies).
RAISE EM HIGH
on it.
See this item? It is called a pretty flower.
What does it do? ...God knows. But riot gave it to you for free so be nice with it.