Some people simply like to practice endgame and other may be attempting to draw. Drawing in chess is a skill itself.
resigning with Dignity and Respect

I have been playing chess tournaments since 1977 and have seen far too many games decided by goof-ups by someone ahead by tons of material. You can resign if you want to, but if you still have any chance at all, you can try to keep your hopes of a draw or even a win alive. Thinking up clever replies and setting traps can help develop generally applicable skills that can come in handy in less horrific circumstances. Often, an opponent who goes up a whole piece stops thinking and looking for threats against him. That's when he's doomed!

down two pieces sometimes is even okay against certain opposition(like those that don't spend their lives studying endgames;D)
I play on if I don't think my opponent knows how to finish. I don't play on if my opponent has shown they know how to finish and their are no traps to be set

If it's in endgame and I know there is no real way that I can win, I will resign. But even if I loose a queen in the beginning; I will still play, maybe I should just move on but I like to give the other player the satisfaction of completely beating me.

If you feel your opponent is holding out rather too long, you can always humiliate him, like performing a bongcloud for example.

I never resign the moment I lose the material, I'll always play at least 2-3 more moves to exactly how much if any compensation I have.
If my opponent is rated many points below me, then often a tough defense can get a draw or if the defense can hold long enough you're basically just giving them time to make a mistake, after which you may even win.
Against equal opposition it's showing not much fighting spirit, imo, to immediatly resign, while playing till nearly checkmate is mostly considered rude.

like performing a bongcloud for example.
As much as I would love to give a Bongcloud to every person possible, it is a little to late in the game to play that move.
I would love it indefinitely if I could play Bongcloud and nothing happen to me.

"Here is a perfect example why I almost never resign."
It's all a matter of perspective, when you are rated 880 and your opponent is rated 744, then anything can happen next (the game is almost a lottery, anyway... last blunder loses). When/if you put another thousand points on your rating you will see things altogether differently. Grandmasters don't resign just a pawn down to be kind to their opponent, they resign because the contest has finished. There's a sliding scale and the nearer you get to the top, the earlier you resign (in general).
Well, you should understand that here you have CC players. They have no connection with OTB play and therefore they don't know that playing on in a lost position is a lack of respect towards your opponent. Many of them, even rated 2800 here have no idea when a position is clearly lost. All they can do is take a position, analyze it for 3 days and produce what they think it's the best move. Because they have time to analyze each and every possible move, they don't need the ability to evaluate a position and many of them are unable to do it.
Enjoy below an example where a top player here (close to 2900) plays when a knight down, then when a rook down, then he plays on even with a lone king against a rook and a queen. His opponent was a GM.

Being down in material does not per se determine the fate of the game, since positions may still arise that could lead to equalization or even victory.

There's a difference between a lost position (like 2 pawns down in an otherwise equal middlegame - complitelly playable) and completelly hopelesly lost (K+Q - everyone should be able to win this)

There's a difference between a lost position (like 2 pawns down in an otherwise equal middlegame - complitelly playable) and completelly hopelesly lost (K+Q - everyone should be able to win this)
Obviously! But the OP was not, I believe, referring to this type of extreme inequality.
Well, you can look at the game I posted above. It's clear that the CC players have other standards than the normal chess players. We might say that they don't have the dignity to resign when a rook down against a GM, but maybe they don't know that a rook down is decisive material.

Well, you can look at the game I posted above. It's clear that the CC players have other standards than the normal chess players. We might say that they don't have the dignity to resign when a rook down against a GM, but maybe they don't know that a rook down is decisive material.
A rook down (or a minor piece) against a GM, IM or NM is one thing. A pawn or two down here in chess.com is another.
Additionally, I think most of the members here are "normal" players; what is different is not their general chess "standards," but the framework of the competition. I, for one, use the same standards in CC that I use in OTB.

What's the big deal??!
If you are way ahead in material, snuff the guy out. If the person has a higher rating, they are basically banking on the prospect that you are going to botch the game.

Prawn, why did white resign in your "perfect example"?
I didn't give an example... the inverted commas are intended as quotation marks. I was quoting a part of another post (the post directly above mine! {post #9}).
My comment didn't require a position/game/example as it was a remark in general and not particular.
It always fascinates-being a reasonable novice to this fascinating global game, that many players -often with superior ratings and experience-choose NOT to resign their position when they have lost major pieces and are in an unsavoury poistion on the board!
Why do this and what are the perceived benefits of extending the game when apparently 'down and out' -just so I can learn and pick some 'tricks of the trade' while adding to my exepeience and playing pleasure?
Comments please