alt Hacker News> do better
I find that expression far more offensive than ‘fuck’ or ‘shit’. Similarly (and non-exhaustively): ‘bad take’; ‘not a good look’; ‘this ain't it’; ‘… not the … you think it is’; ‘…, actually’. They're all personal insults. “This code is crap” is fine; “You're crap” is not.
As I see it, there's nothing offensive about "do better" - it's just asking the person to not repeat the same (ostensibly misguided) thing they did before.
On the other hand, there's Kratos's “Don't be sorry, be better”, which did hit me hard when I reached that part in God of War 2018. That one hit me on a very personal level.