I was once on a Greyhound bus where a guy was loudly talking on his phone, but not on speaker. The issue was he was just repeatedly saying:

“Listen… Listen… Listen… Listen… Lemme tell you… Listen… Listen … Listen lemme… Lemme tell you … listen”

For half an hour.

Finally a hero yelled out: “Listen! Lemme tell you to shut the fuck up!”

He said “lemme call you back later” hung up and shrunk down on his seat as the whole bus clapped.