Colleagues next to me eating hard carrots, chips, anything crunchy. Or Chinese expats who slurp their soup and coffee (normal in their culture; rude in mine)... it drove me crazy.
The singing one drove me insane at my last job. An office lady walked around the office, she would loudly and falsely be singing nonsense like: "LALALALA POMPOM PIEWPIEW LALA" (verbatim) and sometimes fragments from pop songs, in her broken English: "I CAN'T GET NO SASIFICTION LALAPOMPOM".
I wanted to murder her. No joke. If I could get away with it, I would have. The anger was physical and deep. Rage and disgust was the feeling, and I felt personally attacked. It felt like a "fight or flee" instinct, where I'd prefer to fight.
Many angry looks thrown at her (not just from me!) didn't make any difference. She must've felt like she was a rock star or something.
On my last day in the office I mentioned her to the rest of the office. Turns out everyone was annoyed by her. Nobody spoke up.
I have misophonia. The hospital close to my home in Amsterdam did a lot of scientific research into it. And nowadays I work from home, fully remote, as a software engineer. Life is good.