Irregularities. Each 'level' has its characteristics, and players get used to them. You do the same when you're climbing, because it's usually a gradual climb. But, when you abruptly descend into the levels below you then experience irregularities, for a short while at least.
Why people at low 1000 are harder to win against than 1400-1600 players?

They're so tough you resign in the middle of a game with equal material for no reason
https://www.chess.com/live/game/3083475925?username=laurentbaptiste
https://www.chess.com/live/game/3087647580?username=laurentbaptiste
Even tougher than that, you resign right after you win their queen
https://www.chess.com/live/game/3083488859?username=laurentbaptiste
I dont seem to understand why go off topic? I'm not talking about the quality of MY play, I'm talking about the quality of THEIR play. I never said I was the god of chess. Pls stay on topic and dont be toxic.

Oh I see, I should've waited. You tricked me @Farm_Hand. I could've been praised by @LaurentBaptiste.

Still, I find them harder to play against for some odd reason.
The highest rated player you've ever beat was 1445.
Your all time win % vs players 1400-1600 (as per your title) is 17%
Your all time win % vs players 1000-1050 (as per your title i.e. "low 1000 players") is 100%
Your all time win % vs players 1000-1099 is 73%
So you play MUCH better vs 1000s than you do 1400s and 1500s (and you've never played a 1600 in blitz).
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Having said that, sometimes lower rated players feel tough (even if we win) because:
1) We expect ourselves to win easily, so any difficulties we perceive as them playing better than their rating.
2) They play unorthodox moves because they don't know any better. Awkward openings or desperate attacks may make our position winning, but we have to calculate more than usual to deal with the strange positions... and again extra work is interpreted as them playing well.
Yes, probably. When playing at the 1300-1400 rating I felt like I could focus a bit more on positioning. Against 1000 players, it's all tactics. I think I may have misjudged the situation, I never stopped to look at the statistics. It was just a "gut feeling".

So when I joined I stayed around 1300-1400 for a while. Doing ok against people that level. I even managed to go 3rd in this tournament:
This tournament is rapid by the way.
Rapid ratings are typically higher than blitz ratings.
A new chess player would probably be below 800 in blitz, but might be over 1000 in rapid. Two different rating pools.
Additionally I may look like I resign too early but that's because I had the impression keeping on playing when I judge I'm on either material or positional disadvantage, is not very polite. As in, dragging the game. So i prefer to concede and start over.
On the other hand, I've lost many games when my opponents did not do just that when I'm ahead, and then I blundered and they took the game
It's not about politeness. You should play on. Positional disadvantage is something not even GM's resign over. You should learn to come back from material disadvantage
There is a way people at every level play. The way 1000s beat each other is by going for cheapshot attacks, hoping for one move blunders. When a higher rated player (like myself) plays them, their aggresive playing style catches players who assume their opponent to make more depth-based decisions off guard, therefore making it much more difficult for a higher rated player to not blunder against a 1000. The same thing applies for most levels, although there is of course a cutoff at around 2000 or a little less where players get so good they do not make one move blunders without time struggle.
So when I joined I stayed around 1300-1400 for a while. Doing ok against people that level. I even managed to go 3rd in this tournament:
https://www.chess.com/tournament/live/1510-rapid-978621
So I had a really bad run for a few days some time later, as I'm a bit inconsistent. Dropped to 1100 rating. I said ok, easy to get out. Unfortunately I'm getting outplayed in every single game now. I just can't climb and, actually, I'm sinking even more ... People at 1000 rating seem to be more accurate and play better than the ppl I used to play against at 1300/1400, even some of the 1600 I played in that tournament.
Why?