A colleage of mine had a former colleague pay a surprise visit (someone who worked here a bit before I did). This is undoubtedly very nice but they've been having a really loud conversation about 5 to 10 metres from my desk for the last hour and a half, thus making it nearly impossible for me to focus on my work, or anything else for that matter.
And I've no doubt that when this conversation finally ends she'll then head off to lunch leaving me alone in the office for an hour and having to answer all the calls etc. so I'll bascially go 2 and a half hours without being able to get anything practical done and thus have a load of work to catch up on.
What's pissing you off today?