Basically you just name those horrible moments in games that make you groan, rage, cry, etc. From throws to missing skillshots.
I'll start: That feeling when your playing a close game against a Tristana and she gets that god-forsaken hopscotch Quadra-kill costing you the game.
Seeing 2 low-hp minions in lane, don't manage to decide what to do, miss both and proceed to miss a third one out of pure frustration.
When you step on an ap teemo shroom
fuccing 
That feeling when you're playing against a fizz. I think that's enough said.
When you get a quadra kill, and the first thing your friend says is, "Nice job killing the wraith camp." .___.
Yes, that's happened to me, haha.
That moment when Karthus requims after a teamfight 
PENTAKILL
When you cant play because you lag too hard due to server instability and your team rages at you -_-
That moment when you try to get a fade-away ignite kill but they survive
As Caitlyn, I get a perfect ult lock on to the enemy carry as they escaped a fight with really low health.
And then... 
headbutts their full health Leona INTO THE PATH OF MY SHOT. Then blames me for hitting Leona with my ult and not their carry.
That feeling when you get your first penta kill ever, and then aatrox steals the hexa.
https://www.youtube.com/watch?v=GwiCuY7rZDU&list=UULTd-jrWMZPbAPCH7Gx4qLg
1:54 - 2:02
Here is video proof of me heckling my lane mate for eating EVERY SINGLE SIVIR 'RANG. Watch the rest of the vid and you'll see what i mean.
Finally land a spear with Nidalee against those creep-huggers, jump in only to have them use their own jump away. Now left in a bad spot to die. Again.
When the enemy jungler invades when you don't expect it and your allies don't notice your pings.. 
When your team blitzcrank flashes right next to the enemy and still misses his Q
That moment when you have the perfect ult set up. Your ult is flying to the certain doom of an enemy champion.... and then your team's Blitzcrank pulls them out of it.
Had this happen to me as Ziggs. If I recall right, I was having a very hard time getting any kills that game, then that happened. Was a bit upset with my friend over that, but couldn't stop laughing either.
When an enemy just cant seem to die. One game I lost 9 kills to an enemy who escaped with less than 25 life. -____- And it was fizz. same thing happened with zed. and even worse with TALON! he lived barely 13 times. these events have brought me to- in any draft- ban all 3 of them. They are sooooo cheap -__-
>
BEGONE YOU PESTS
That time when Volibear throws Swain into the middle of your team and he doesn't die because ult. So many times.
Later that game, I was escaping and then Swain air drop! >.<
Catching a player out of position and proceeding to kill them but instead they Zhonya's Hourglass, and 2 sec later their team comes and wipes us out or helps them get away.
2.5 sec immunity OP (wheres the AD equivalent....)
Towerdiving that 15hp Lucian as Jinx... missclicking TWICE hitting turret with rocket launcher, being forced to flash away to not die from tower instead of just running away with passive.
Happened to me in my promo... fuck promo-jitters.
That feeling when you solo queue up and the team looks amazing and despite everyone calling out their own roles, someone else joins your lane and starts tower diving like a bad impression of Greg Louganis.
So many examples for that: When you're Karthus/Zyra/Malzahar/anything that does dot/delayed damage and your adc flashes to get enemies about to die to you. When shaco ganks you to moment you're winning a 1v1. When you're support and your adc disconnects. When you flash in the wrong direction (alternative when you flash over the wall right into an enemy you didn't see). Getting your main in aram and someone doges. And my recent favourite: When you ult as brand and it doesn't bounce/hits 4 minions. Makes you feel like an idiot.
That moment whenthe tank goes for the adcqnd your team clump and alistar, amumu, and yasuo ult on them and the disappear...
TMW a fed 
ults you and your team and you all just sit around hopelessly.
When the enemy kills your Anivia egg :(
That moment you get solo killed by 
No matter how it happens, you feel like you got outplayed horribly
that moment when you try to make a fancy zed play with your ult ult in get them to about 1/5 health left and use your ult to get out of there meanwhile, your team's jinx main ults from the bot lane jinx gets the shutdown, all of your teammates and the enemy team says, good job jinx. so frustrating when it should have been me getting the pat on the back and the cookies
