I'm absolutely kicking myself for not saying something at the time but I was so shocked I didn't say anything at all. Just sat there with my mouth gaping open. A colleague said "meh it's nothing" but I'm livid. 
I'm a HR manager but I also recently started looking after the maintenance of the building. Apparently we have a contractor who does all our odds and ends around the building, I called him last week and he didn't answer. We ended exchanging texts and I told him I will next be in the office Weds/Thurs/Fri. He said he'd try get in Wednesday but never specified a time or let me know he was coming.
My diary is usually full up on the days I'm in the office but I was in a meeting, potentially dismissing someone. My office door was firmly shut, my office is completely frosted glass but you can see whether I am in a meeting or not.
Contractor (who I've never met) stands outside my office mouthing "are you X?" and I nodded (still in the disciplinary) and said I am in a meeting. Didn't think anymore of it.
About 5 minutes passes and without even a polite knock, contractor barges the office door open and says "I'm sorry, I'm not waiting any longer" and proceeds to engage in full blown conversation, telling me in a sarcastic tone about the stuff he'd fixed. You can clearly see there's someone very upset and two managers!
AIBU or is this totally unacceptable? I feel stumped on how to bring this up the next time I see him! He looked like he'd cave my head in with a spoon and I feel really silly getting worked up about approaching him. But it needs sorting, right?
Sorry, what a boring AIBU 