Why are all the 800's so good?

I saw people at 800 at their so good. also all the 800 puzzles are impossible

I actually the same question. Somehow it took me a while to get to 1000, but I see 800s playing fantastic openings and incredible middle game tactics.

As a 750 i will say, we do see many advanced tactics, like rook sacrifices, just the reason we're 750 is that we blunder our queen in 1 move : p

I've watched plenty of 800-870 games and I see hanging pieces, missed tactics and big blunders. The main reason for these mistakes is because they are playing rapid at blitz speed.

Look who's talking

You serious dude? My 400 elo friend can solve 1200+ rated puzzles

When i see someone premove in an opening... in a rapid game, i just instantly know "oh this guy's bouta hang their pieces" and also "oh dang i gotta manage my time now"

Maybe they play a lot of chess

In my experience, 800s do know a lot of stuff. They're just terrible at blunder-checking and have trouble considering what their opponents can do in response to their threats. And of course, you'll always get the occasional Tal-wannabe who attacks like a madman but folds like a cheap suit when their "big" attack fails.

The same things often apply at my current rating. The main differences are that folks hanging an entire piece is a bit more rare and they're usually more careful not to come forward with guns blazing when their "guns" are in fact empty. And if you do get paired with a Tal-wannabe, chances are they'll at least be smart enough to not bring the queen out on move 2, though they'll still crash and burn if you know what you're doing.

"Good" is relative and subjective. Perhaps some specific puzzles or games you'd like to highlight?