Short story: A man on a bus is observing passengers all talking on watch/phones, then electronically disrupts their communications.
Possibly a Ray Bradbury story.
This is Ray Bradbury's The Murderer
"Then I got the idea of the portable diathermy machine. I rented one, took it on the bus going home that night. There sat all the tired commuters with their wrist radios, talking to their wives, saying, 'Now I'm at Forty-third, now I am at Forty-fourth, here I am at Forty-ninth, now turning at Sixty-first.' One husband cursing, 'Well, get out of that bar, damn it, and get home and get dinner started, I'm at Seventieth!' And the transit system radio playing 'Tales from the Vienna Woods,' a canary singing words about a first-rate wheat cereal. Then I switched on my diathermy! Static! Interference! All wives cut off from husbands grousing about a hard day at the office. All husbands cut off from wives who had just seen their children break a window! The 'Vienna Woods' chopped down, the canary mangled! Silence! A terrible, unexpected silence. The bus inhabitants faced with having to converse with each other. Panic! Sheer, animal panic!"
"The police seized you?"
"The bus had to stop. After all, the music was being scrambled, husbands and wives were out of touch with reality. Pandemonium, riot, and chaos. Squirrels chattering in cages! A trouble unit arrived, triangulated on me instantly, had me reprimanded, fined, and home, minus my diathermy machine, in jig time."