Reading the post and comments on Softbank plans to cancel out angry customer voices using AI made me think it could be an interesting topic to chat about.
I think the best support I received was in the chat application and service Slack. A competent, friendly human responds. I had two or three support inquiries with them.
The last issue I had in Slack was when I opened via try icon click my clipboard content was being pasted. I was surprised they were able to identify the issue which was due to a third-party application that had only just released with the issue a day earlier. Slack support was responsive with a first message before the solution, and fast to respond with the second message with the identified cause.
I'm not sure any stand out as particularly awful for me. [Kinda] Bad seems to be the norm. Sometimes bots sit in front of being able to write a message (my bank, I have to write the same inquiry a second time), sometimes the first response is automated or templated, sometimes the first response is automated and immediately but a human will follow up, sometimes you call and can hardly understand them because of accent or even awful intonation. Often you receive incompetent answers that don't respond to your message or issue. Sometimes they're unwilling or incapable of resolution or agreeable conclusions.
The absolute worst customer service I ever had was with AT&T and eventually I just told them to go stuff themselves. I switched carriers to Ting before it was owned by Dish and it was known around the industry for its customer service and it was absolutely fantastic.