What do you thing is the most annoying StarCraft alert?

I have the 'I can't build there' from a SCV and Zerg muta sound especially when yout stacking lol

 

1. nuclear launch detected - SH**!!!!! WHERE, WHERE, WHERE???
2. addtional supply depots required - dammit, gotta build another supply depot

 

I find it annoying how the Terran alert messages have the same alarm-like sound before the cyber-woman says something.

Like, I will be messing around with my base or expanding and then I hear "DI-DI-DING!$#@" and I immediately think the enemy is harrassing me, so its like "oh, great, here we go again " and then I hear "Upgrade complete",

'...phew'

still annoying though.

 

That annoys me as well, but I mostly play Zerg anyway.
The most annoying:
"You must construct additional Pylons."

But that's mostly caused by the Blizzard site warnings...