gg etiquette?

I saw a lot of people saying gg after games ended and I thought that was nice especially when I lost badly and was worried the other player might be annoyed at not getting strong competition, so I started doing it too, but now I've gotten in my head about whether there are unspoken "rules" I might not be following. Do people say it after every game, no matter what? Or only when they lose? Only when they win? Only if it was a close game? Is it ever rude to say gg? Am I overthinking things?

I've tried to pay attention to see if there's a pattern but I pretty much forget as soon as I'm in the next game so I'm not sure. I'd hate for what's meant to be a friendly gesture to offend anyone.

*Bonus: If anyone says "gg" to you in a context that seems rude, just assume it's me, a doofus who's trying to be friendly! It might not be me, but the friendly part is probably true anyway, and even if it's not you'll feel better thinking you just played with someone awkward but well meaning instead of a snide jerk of some kind