Tactful ways to inform people that they're playing badly?

[Vahlnir]

With all due respect, I understand that you may have not been bothered by it, but...I still would be, and when interacting with somebody, the only person's reaction that really matters in the situation is the person you're interacting with. For example, if you tell an offensive joke, some people may or may not be bothered by it, but just because some are not, doesn't mean that those who are lose the right to feel offput by it. Now of course, as far as the tank pulling thing goes, all of this is all just hypothetical, the guy didn't actually talk about me or my way of pulling, but I'm just trying to get my point across.

If someone is trying to make an unnecessary comment about my gameplay just because they want it to be essentially perfect (according to their definition of perfect), I find that to be a bit narcissistic, annoying, and intrusive. Imo, it is a small nitpick. Because if I don't stop doing it/change the way I do it, we'd still be fine. It's not as simple as "if it helps, it helps!", no...if youre trying to completely dictate/disrupt someone's comfortable playstyle because you see a few minor things you don't like (because of trivial reasons that wouldnt even have any serious effect on a run), then you're not helping, or at least not in a way that is meaningful. You're just gonna annoy your group members, your teammates, your peers.
And a team that cannot cooperate is worthless.

There's nothing really offensive about it though. And just because someone has a playstyle that they are comfortable with, that doesn't always make it an ideal one or one that works well with others. The 2nd one is the one most people are concerned with, because it is their time being spent too. I'm of the opinion that people should always be open to improving themselves. Some people simply can't and that's okay. I don't judge. I never expect perfection. It's the ones you hear "YOU DON'T PAY MY SUB" or "WHO CARES?" from that I find intolerable.

Something like pulling mobs in an efficient way isn't a trivial thing. The tank dictates the pace of the run. As such, they are also responsible for their party members since they are supposed to be taking most of the punches. If other players are also taking those punches unnecessarily...that's an issue. A significant one. And that certainly warrants some advice, solicited or otherwise. When I'm not playing GNB, all I really care about is that the tank holds onto what they're supposed to be pulling. I don't care about their dps. I don't care about their rotation. I just expect someone to do the basics like holding aggro. And how a tank pulls affects how well aggro is held. Doubly so if they are new and/or don't know how their job fully works.