I can NOT stand when someone uses the “last” of something and doesn’t replace it.
I can NOT stand when someone takes something from where it belongs and leaves it somewhere else
I can NOT stand when people don’t use their blinkers when turning
I can NOT stand when people chew their nails/hair
What really urks you?
Tardyness! It should be punished! I detest having to wait for people, if you say you are going to be at a certain place at a certain time, just be there!
Also slow people at ATM’s or even worse the automated Ticket sellers at movie theaters.
MtM
People wearing headphones and playing their music so loud that I can hear it too.
The same goes for people playing their music in their cars so loud that I can hear it in my car. Especially if it’s actually painful to me.
People who start threads I’ve been thinking about for two days before I can get to it! 
Dumb new rules at work that my sandals have to have a backstrap. (But at least I’ve got an excuse to buy new shoes now!)
People who do half-assed jobs and think they should be praised for the work they did.
The rain that won’t stop!!!
I know it sounds uppity but it irks me when people use poor grammar or spelling. All the time. Even if it’s the basic misuse of there/their/they’re or your/you’re or to/too/two. I’m not even an English teacher, but gahhh that ticks me off.
Ditto on the music-so-loud-my-eardrums-throb-from-the-pounding-bass. I have sensitive ears to begin with but wtf?
Friends of mine and I use “eh” (not the Canadian ‘ayy’ but more like ‘so-so’ or ‘whatever’) in conversation, either in person or online. But I HATE HATE HATE when one particular friend says it because she uses it as such a brush-off, especially when she’s asked for advice and then thinks your idea is lousy. Whenever she says it online, I immediately close the IM window because it pisses me off soooooo much.
(I meant when she has asked for advice)