That sounds like an infuriating experience all around

holding and staring at their phone with loud successive incoming notifications

I despise this. I personally don't think that anyone should ever have to hear another's notifications at any point but when they are using the phone I want to make them swallow the thing. A woman in my tiny shared office leave her phone at her desk with the sound on and her family likes to call her in batches of 3-5 one right after another as if there is an emergency every single day of life.

One time in a library I was studying for an exam and a guy was wearing headphones that were connected to his phone, but they must have been slightly disconnected because his phone was playing in the open air and through the headphones. he didn't realize it but fuck was it annoying. He spent about 10 minutes testing all of his different ring tones, notification sounds and alarms options, picking which he wanted to use permanently Im guessing. someone finally said something after 10 minutes of that. It must have been a new phone for him I'm guessing