The golden rule appears in many religions in different ways, but can be summed up as “treat others how you want to be treated”. However, I’ve seen it misused in some extreme ways in the past. What’s the most out-of-left-field way you’ve seen it used?
I don’t know about “out of left field”, but I’ve seen many people use it to justify being retaliatory. “They treated me this way and did a horrible thing, so this is the way they want to be treated! I’m going to do it right back to them!” That’s literally against what the rule says. That’s just you giving them permission to continue.
In fact, I think that’s depressingly common.