Team Fortress 2, as Spy.
Eternal Reward. Disguised, about to backstab an Engineer and sap his Sentry (backstabs with Your Eternal Reward don't alert a sentry). One step away, about to make the critical sta--
BEE-BEE-BEE-BEE *missle launch sound*
That is the sound of my computer lagging, me undisguising myself by stabbing and missing because the lag made me stand still, the Sentry turning around and blowing me up.
FUUUUUU
Okay. Let's try again.
On my way to the Sentry, I see a Sniper. It probably saw me coming up, because it had its Kukri out by the time I arrived. I need a backstab for a disguise.
We stand at opposite ends of a hallway-like area. The Sniper is... I'd say ten feet away. I'm waiting for it to charge forward, whereas I'd run forward, do a quick 180 and backstab it (done it many times before). HOWEVER, the Sniper swings at me while running forward, clears maybe half the distance (five feet) and kills me.
Let me repeat: it was around five fucking feet away and killed me with a melee weapon.
I hurt my throat screaming at the game.