"Then find another job, when you're in a better mood this experience will go much better."

I am usually in a great mood when posting for jobs. It means I get a new opportunity and can learn new things.

"Catch their manager walking by and invite them in for coffee, when they see the cross-team communication and camaraderie they'll think it's the best thing ever, especially as it is self-formed and not HR-driven drivel."

I used to do this in the office, but it is a little more difficult when WFH. I do try to strike up some non-work conversation when I find out a personal fact about someone else, like a shared interest.

Thanks for all the input!