I had that feeling a couple of times in 3 day live where a player is down big(i.e. a king to 5 pieces) and they don't resign instead prolonging the game. I usually like to send one or two messages during games which normally has been met very friendly, but I do get a good and bad feeling when an opponent makes a larger blunder.
likes and dislikes for people you don't know
I thought I was the only one, some players you just take a dislike to, seems irrational but its true. I guess we all have a preference to the type of game we enjoy so if a players style jars with your style its a less positive experience.
Perhaps the labels assigned are not "accurate", but it is certainly natural. In a short game where we do not know the opponent (in person) - quick judgements are actually inevitable. Psychology studies indicate that when you meet a new person, we make our judgements of them within two seconds! Likely, this is an automatically triggered reaction to the situation. Probably the username, avatar, and even the chess moves played all contribute to your judgement on this person. These judgement actions are not inherently " bad", but they often are more difficult to alter - even after you learn more about them (this may be "bad").
Into the game, it is possible to understand a bit more into the opponent's thinking process - and in turn you may learn more about them than one may expect. For example, if they take a long time on a move - this is an indicator that they are thinking over the board versus memorizing theory, for this situation. Hate to say that I have made a friend by a chess move, but I have sometimes viewed people more positively after I see an idea I had not previously seen (could be a brilliant tactic, creative opening that I respect, an instructive chess maneuver in a closed position etc.); it sounds a bit silly, but this fact is sadly more true than I might like to admit.
Of course, the best way to really get to know your chess opponent (other than meeting in person) is to simply check their chess.com profile. Even this may not really be adequate for " knowing them", but it is miles ahead of just snap first impressions via a computer screen that is literally lifeless.
Do players here also encounter that when you play against people you've never met, that one developes strong likes or dislikes for the opponent? It's not rational or based on anything. I even hated one or two players and I can't say why. Is that normal? On the other hand I can feel sympathy for a player too. Also without rational base. The person on the other side is only a name with a nationality and a rating and he or she is moving virtual pieces on a virtual board.