The Most Common Scenario That Makes League Suck, IMO
To put it simply, its when Riot wastes your time. I elaborate on the specific scenario below:
Step 1: Riot assigns auto-loss randoms to end your win steak Step 2: Auto-loss randoms do what they do best Step 3: Auto-loss randoms refuse to surrender at 15 Step 4: Auto-loss randoms refuse to surrender at 20 Step 5: Auto-loss randoms refuse to surrender at 25 Step 6: Auto-loss randoms refuse to surrender at 30 Step 7: Auto-loss randoms flame and report the surrender voters (the same ones that actually played well and did their job) for "giving up" and not "playing for the team" when the accusing players are somehow oblivious to the fact that they are liabilities that ruined their team's experience.