I'm going to be in the minority here, of course, and I'll tell you that I absolutely hate it when people tell me "gg", regardless of whether they win or lose.
I'm someone who despises what I call "fake politeness". What I mean by that is I extremely dislike when people do actions disingenuously, either because they are lazy or because it's something they "have to do" despite what the other person feels. Why would anyone waste their time saying or doing something they don't mean? I don't see much difference between this kind of fake politeness and simply lying. I prefer real interactions with real people who actually mean what they say. There are people who are the opposite of me who prefer having people put on a front and say things they don't really mean. I don't understand it at all.
I've heard the arguments that "gg" is just shorthand for all the long things that they want to actually say. Well, that signals to me that they simply can't overcome their laziness to say what they want, which makes their "gg" worthless at best and insulting at worst. I'm not worth being told what you actually think? Well, that would just make me think poorly of you in my eyes.
When it comes to saying "gg" first when you have won the game, this is further not taking into account the opponent and what they might think or feel. Games are about competition. Winning and losing matters. There is no benefit to losing other than "Well, I can't do that again." The winner receives all the benefit, especially if it's in a tournament or there is a championship on the line. So the loser has to deal with failing to achieve the goal of winning the game (whatever the stakes) and now further has to deal with the winner telling them a lazy "gg", all while the loser has to just grin and accept it like it's no big deal, lest they incur social consequences for not reciprocating a meaningless gesture.
When it comes to a loser saying "gg" first, this is just a sign of submission. They accept their defeat. Okay, great? I can clearly see the score sheet that tells me I won, why do I need your acknowledgement of this reality? By not saying "gg". you can't acknowledge you lost or something? Are you worried I'm going to look down on you personally?
You see, most people who say "gg" don't mean it whatsoever. They have zero intentions of having a genuine interaction with their opponent. They do it because they feel they have to, even if they don't want to. How does this make a better community? I've seen some people say that getting mad at "gg" is like getting mad at "Good morning". No, they aren't remotely comparable. A "Good morning" can actually be genuine and heartfelt. "gg" can never be this. Even in person, "gg" is still disingenuous and can never have real meaning.
I find it interesting how some of the same people who complain about opponents conceding late in the game because they "can't take 5 seconds to finish it out" are the same people who say it's say it's okay to do a meaningless "gg" to save time. I see them having contrary positions that kind of defeats the their points on both fronts. In the end, it's just better to say nothing at all than to perform a worthless gesture.
I'm sure the replies are going to be fun, lol.