I would take it well. I was only going to find out for myself later on, they're just helping my analysis!
Also, on the topic of when players play their best- a lot of people have opening knowledge far surpassing their endgame and middlegame skill. Unfortunately, this always comes back to haunt them!
The game is fine to be ranked linearly, for it is the measure of all the elements of your play combined into one rating. Just be sure not to compare it to a rating anywhere else but chess.com!
Yes, you can always take multiple indices and combine them in some way, perhaps with an average, to simplify them into a single number that can be used to rank linearly. My point was only to say that a higher rating must be understood in this way, and not in the stronger sense of "by virtue of beating you, and having a higher rating, I know everything you do, and have nothing to learn from you". If we imagine a Venn diagram, then I see circles of all sizes, but almost none of the smaller ones are entirely contained by the larger ones. Well, unless the larger one is MUCH larger!
I'm beginner on the chess.com, that's the reason I grasp an opinion and a remark of my more skilled opponents with my respect and attention. It happens useful sometimes! 
well, I would hope that you would let me know when I make one of those mistakes, cause I do know that I tend to make silly mistakes throughout the game and my end game seems to be lacking. I would never take it as you trashing me, or my game (in fact, I think I have in the past asked it of you). If I do see something you do that confuses me, I might ask about, it may be a training thing for you, or for me, we should learn from eachother.
Thank you C, that sounds reasonable!
Yes, I would agree with that. But my point was that they are out there, and in here, too. So caution is required when dealing with such psychos who are prone to take offense at such innocent remarks.
To be honest, it would annoy me a little. I mean if I'm up enough and lose it's very obvious that pointing out I could have won is of absolutely no help (it would be easily known by both players) and I just feel like "why do you need to emphasize that point? You think I didn't know that already?". It happens, but I don't see the need to talk about that, unless the advantage was only like a pawn (which may require more accurate play) but if you were up a rook then basically the only improvement you needed was to not blunder.
Yes, if they knew. But what if they did not? On the one hand, you can help to improve their game. On the other, you may annoy them, as you say.
Go mind reader
Well, since I cannot read minds, I have no idea what you are talking about.
Yeah if there was one specific move they missed, which was critical to find, then sure, tell them.
Thank you Elubas, that was more what I had in mind. It wasn't so much a vague notion of there may have been some line that might have produced a win, but rather right here, at this move, had you instead done that, check mate.
Yeah, I'm busted! But despite all of my time spent here -- or maybe because of it? -- I actually remain productive!
if it's a blitz game, you say nothing. anything you say will be obnoxious because of the context. only in longer time controls can you do things like this.
I think that's fine, saying "I think you had me at move 32.____ or something similar.
In longer club games (about what they call standard here) it's pretty much standard practice to go back to any positions of interest where you want to point out or explore a possibility. But like Elubas said they're critical positions, not what you think are inaccuracies (and like you said people are interested in learning something). I've had a number of great learning moments when after a game my opponent points out the moment I went wrong.
If it's a stronger player and I don't want to offend them (lets say I barely won) I'll say something like "what was your evaluation before the bishops came off" to get them talking... just because you won doesn't mean you saw everything they did ;)
I think that's fine, saying "I think you had me at move 32.____ or something similar.
In longer club games (about what they call standard here) it's pretty much standard practice to go back to any positions of interest where you want to point out or explore a possibility. But like Elubas said they're critical positions, not what you think are inaccuracies (and like you said people are interested in learning something). I've had a number of great learning moments when after a game my opponent points out the moment I went wrong.
If it's a stronger player and I don't want to offend them (lets say I barely won) I'll say something like "what was your evaluation before the bishops came off" to get them talking... just because you won doesn't mean you saw everything they did ;)
again such things would be fine in a real tournament, in real life, but in terms of an internet blitz game? yeah, no. you don't say anything. because it's meaningless in any case.
Many, many times I have gotten destroyed early in the game, and then somehow managed to come back and win. This is not a testimony to my brilliant end game play, but rather points to the fact that I play against some players who are stronger in the early game than they are in the middle and/or end game. In fact, many times I was a move away from being check mated, yet my opponent must not have seen the mate, made another move, and allowed me to live another day, to fight on, and, ultimately, to win.
My question is confined to the games of this sort that occur between me and an opponent who is a friend; not a complete stranger. Although I do use the term "friend" here rather loosely, to include even an opponent playing against me for the first time, as long as the conversation during the game is good enough. In these cases, I am often temped to say "I thought you had me there", or "had you played this move you would have won the game". My motivation is obviously not to say "Ha ha, you blew it, idiot", but rather to impart some chess wisdom. In my world view, we are not -- or should not be -- ranked linearly, and I may have something to offer to even players who are better than I am, and I will certainly be happy to learn from those rated lower than I am. So my offering chess wisdom in no way means that I think that I am better than you.
But I have seen (in these forums) some players taking offense to the greeting "good luck". In my own dealings with others, both here and elsewhere, I have seen innocent remarks taken totally out of context and causing resentment. So, with this in mind, I ask -- to tell, or not to tell, that is the question. If you lost a game, and then your opponent told you that you could have won (and pointed out how), and did so in a polite way, then how would you take that?