People feel happy when they win, empowered. Puts them in a better mood and they say thanks because, like you said, the person took time out of their day to play. However when a person looses the person is frustrated, confused, and insecure and sees that the winning player made them waste alot of their time. It's all physcological.
why do people say thanks?
The batlle on the table is magnificent.Leave the soles trails and rejoice to a defeat as a victory if the game was great
If you're truly bothered by their vainness and narcissism you could always listen to subliminal confidence messages on youtube while playing:)
In all seriousness, it's like anything you try to get good at. You just have to learn to ignore their imperfection and continue trying to be the best person you can be. Don't let others deter your way to improvement.
People feel happy when they win, empowered. Puts them in a better mood and they say thanks because, like you said, the person took time out of their day to play. However when a person looses the person is frustrated, confused, and insecure and sees that the winning player made them waste alot of their time. It's all physcological.
Also psychological is when in that frustrated, insecure state, if someone says "thanks" it might stick out in the person's mind.
After winning, if the loser says "thanks" the OP wouldn't remember, because who cares.
Similarly when people believe "I only disconnect when I have a winning position, so my opponent made it happen!"
Disconnecting in a winning position has a stronger emotional impact, so it's quite memorable. When they disconnect in a losing position they forget about it.
Seems like people are even offended by niceness these days.
https://www.youtube.com/watch?v=DM4-r4pN1PY
I don't say "thanks" or "thx"; I say gg (good game). Especially if they blundered and lost in a dozen moves.
I'll only say thanks or thx if we play a few games in a row together (and if they're not being a jerk in the chat).
I never say gg. But if I think they played particularly well I'll say well played.
I always report people who say ' thanks' or ' gg' to the moderators. I find it irrelevant , very unhelpful and it is certainly not very nice given the amount of things it could mean.
I say sometime goog game, or thks ever if I lost, because it'is a chance to learn. but many time I have no respons. never mind. ( excuse my english...)
I am just french ;-)

After I play a game online, a lot of my opponent says "thanks" or "thx" when they win but they never say "thanks" or "thx" when they lose.
What are they thanking me for?
I tried saying "thx" to my opponent when he lost and he got mad at me and said all these profane words. In my case i was thanking him for taking the time out of his busy schedule to play me. i am sure that guy/girl could have spent those 3 minutes doing something more productive in his/her life than wasting the time losing a chess game to me. I explained that to my opponent but then he/she never replied and and left the chat.
Are you one of those people saying "thx" or "thanks" to me? If so, why are you thanking me? No thanks are needed to play a game of chess.