Polystyrene pieces rubbing against each other.
The hooting sound small children make when they're whinging and feel so hard done by, but aren't actually genuinely upset. Especially when it would instantly switch off if ice cream appeared, but because you aren't going to give in to their whining, it continues for hours after they've forgotten what it is they are pissed off about.
Tapping. Not the rhythmic tapping of a child with ADHD or a natural talent for drumming, the irregular tapping of somebody with no sense of rhythm or timing - especially when they are convinced that they are a superb drummer, despite never having had any lessons, and have made a point of coming up and demanding your attention so that he can inform you because you're the only female your band that they aren't as good as the one he nearly hit the big time with when he was 15 but the others told him to sod off because he had no ability whatsoever.
The sound of a mic drop. Seriously, it's the most arrogant, entitled thing somebody can do with expensive equipment. If you do it and it's not your own microphone, just fuck off and die.
Kids who have never been taught to sing, but just shout because that's what they think singing is. Not just because it makes your ears bleed, not just because it's potentially damaging their voices permanently, but because some prat has apparently conned their Head to pay them an extra couple of thousand a year as 'the music specialist' when they've not got a fucking clue. And the Head hasn't fucking noticed and told them to fuck off and run the netball team instead.
The sound of a particular ex-PTA mum sweeping into the building in her expensive shoes. Look, nobody likes you. You're racist as fuck. We don't want to hear your stories of how The Africans needed organising when your husband had a fancy job in Malawi/Rhodesia/Wherever the fuck it was. Or the way you bark at children and bitch about how much the school has changed since your precious children were here being middleclass and white. We don't want you here, but you're best mates with one of the Governors, so you're fucking Teflon coated.
The sound of a guitar that hasn't been tuned. It's not hard - EADGBE - here is a tuner. Use it. I'll do it for you if you can't be bothered to use it. No, for the love of God, do not fiddle with the fucking machine heads again. Just stop playing. Just stop.
The sound of an emerging furball in the dark. Please leave it under the bed, as I do not want to find it under my bare feet or on my quilt. Bastard animal.
The clucking sound of somebody who knows they are allergic to something but likes it so much, they don't care and their throat is now slightly swollen for the next six hours. For fuck's sake, are you actually hoping the next reaction will kill you? because I am
Eating with the intention of everybody being able to see and hear exactly what it is whilst in the process of being mixed up with saliva. Especially if you then noisily slurp a drink mid mouthful to moisten the food to peak sound level.
The snorking sound of copious quantities of snot being sniffed back up so it can be flobbed out on the pavement. Blow your nose into a tissue, FFS. Or I might just have to hoy you in front of oncoming traffic.
The sound of Davinia McShouty. Or Jenny Fucking Chocolate Eclair going on about fucking vaginal dryness. No, it doesn't bother me. YOU bother me honking on about your dessicated minge.
Other than that, I'm an extremely chilled individual. Honest.