I must hear this everyday in the office either said to myself or a co-worker and it annoys the hell out of me!
I dont mind so much when somebody comes over to my desk, goes to ask a question but then realises I'm on lunch and offers to come back later, but it's the people who acknowledge you are not working and still expect you to do something for them or answer their questions (which could definitely have waited half an hour!!)
Anyone else or AIBU?