A shop owner in Korea said gomapseumnida (고맙습니다, “thank you”) to a customer after a sale. The customer walked out, came back in, and let them have it. The owner posted about it in an online community for small-business owners, and Wikitree picked the story up in November 2025.
“I’m not your friend and I’m not your junior,” the customer said, as the owner told it, “so what’s with gomapseumnida?” Then came the word for ignorant.
I get why that rule feels true to some people. gamsahamnida (감사합니다, “thank you”) has the weight of a Sino-Korean word, and gomapseumnida is built on a native one, so it’s easy to hear the first as the grown-up version. Korea’s standard dictionary points the other way.
Gamsa is explained with gomap
Look up gamsahada in the Standard Korean Language Dictionary. Its thank-you sense is defined as 고맙게 여기다, “to regard something as gomap.” The adjective sense is “to have a gomap feeling.” The Sino-Korean word is explained with the native one.
The National Institute of Korean Language said the same thing more plainly in December 2024, when someone asked which of the two to use. Both are fine when you’ve received a kindness, the answer said. The difference is that one is native Korean and the other comes from Chinese characters, and choosing gomapda can be a way of using native words on purpose.
The ending is where the bowing happens
What actually moves the politeness is the last syllables. Gamsahamnida and gomapseumnida both end in the formal style that, in the dictionary’s words, raises the listener very high. gomawoyo (고마워요, “thanks”) ends in -yo, the informal polite style, which raises the listener to an ordinary degree.
That informal style’s definition has one more line that I think learners should hear. It’s used widely in places where the formal styles would otherwise go. So gomawoyo isn’t rude, it’s just a notch less formal.
A question sent to the institute in August 2026 came from someone whose new teammate was a year older but junior in rank, and kept saying gomawoyo to them. The institute said language etiquette isn’t something Korea’s language norms settle, so it couldn’t give a clear answer.
It did add a note. Gamsahamnida raises the listener very high, gomawoyo raises them to an ordinary degree, and if you want to raise someone very high, gamsahamnida or gomapseumnida is the fitting choice. By that note, the shop owner had picked one of the two top options.
Why I lean toward gomapseumnida
If it were me at a counter, or talking to anyone older, I’d use either -seumnida form and not worry about the root. I kind of prefer gomapseumnida, though. It sounds warmer to me, and I don’t think warm and respectful are opposites.
Gomawoyo I’d keep for people I’m friendly with but still polite to. With a stranger it’s not wrong, but it’s the one that leaves room for someone to decide you were casual.
The comments Wikitree quoted sided with the owner. And both institute answers above end the same way: gomapseumnida.