Opening, Middle-game, or Endgame, Which is most critical for improving your chess and why?

#110 very good comparison, unfortunately there are players who believe openings aren't important. You can probably live in an house without a roof but why would you?
I'm sure there are those that think openings are not important. But i also think that its relative to skill level and ability. In the end, people are going to do what they want to do.

You should probably study them all, but your main emphasis should be on the endgame first, later on the middle-game, and focus on openings last.
I think openings first but that was just what suited me when I learned. Openings first allows you to learn how to develop your pieces and begin tactical operations. You only need to learn endgames when you're actually capable of reaching one and when you find that the results of more games depend on skill in the endgame. So openings first.

Openings are of prime importance. Then learn how to conduct a middlegame and finally, learn endings to quite a reasonably proficient level.

i used to not know any endgames and i would always get winning positions againts people better than me than blunder in the endgame so i started practising endgame positions

The vast majority of world champions, lesser grandmasters, and chess teachers, especially those in the Soviet Union, have said the same thing. I would find out what that is. The photo offers a clue.

The vast majority of world champions, lesser grandmasters, and chess teachers, especially those in the Soviet Union, have said the same thing. I would find out what that is. The photo offers a clue.
As you should know, the chess school of the Soviet Union indoctrinated people with that idea. Also it was their aim to try to dominate the chess world. Now, if you think about it for even a second, an "endgames first" approach enabled trainers to spot the likely stars and weed out those of less natural talent quicker than any other method. And that will be why the Soviet school was indoctrinated to think "endings first". No other country, particularly, has adopted such a particular approach, so the Soviet thing has nothing to challenge it. Inevitably, there will be those GMs from elsewhere, who haven't managed to work out WHY the Soviets say "Endgames first". Consequently, there will be some unthinking support from elsewhere, which will add to the impression that such a system is "correct".
It's surprising that no-one else seems to have managed to work out what I just worked out in 30 seconds, three minutes ago. Or was it a second? Could it be because I'm wrong? I doubt it.

Yep.
The Soviet Union did dominate the chess world.
Soviet trainers did use endgames to identify talent.
What other country has nationalized their chess curticulum?

You should probably study them all, but your main emphasis should be on the endgame first, later on the middle-game, and focus on openings last.
That what José Capablanca wrote in what remains more than a century later the best book for beginners and even many intermediate players: Chess Fundamentals

Perhaps the most logical way to learn chess is to start with King and Pawn vs. King endgames - the least amount of pawns/pieces available, where a win is still possible.
The player learns about things like pawn promotion, tempo, escorting the pawn with the king, and about opposition. This also teaches basic checkmates like King+Queen vs. King, and King+Rook vs. King, as those will happen after the pawn promotes ...
After that, the difficulty can be increased by adding more pawns or pieces to either side ...
Little by little, the player masters a certain setup, then the difficulty gets increased by adding more pawns or pieces.
Eventually (perhaps after weeks, months, or even years), the final position (the hardest difficulty of all) would be reached, where all the pawns and pieces are in place: the starting position.

Yep.
The Soviet Union did dominate the chess world.
Soviet trainers did use endgames to identify talent.
What other country has nationalized their chess curticulum?
So you agree I am right.
I just played a 5 mins game and put it on analysis to see where I went wrong. Apparently nowhere although sometimes I didn't make the optimum moves. However, the point I'm making is that the engine, after three moves, shows the Modern Benoni as being about +1.3 for white. I think it should be showing about +0.4 ish.
Therefore new players definitely need to acquire basic opening knowledge in order to counter the silly assessments of this engine on chess.com.
#110 very good comparison, unfortunately there are players who believe openings aren't important. You can probably live in an house without a roof but why would you?