Favorite Korean words/expressions?

Aish is the one I use often????

omo, aigoo, yah

I found myself saying Aigoo and Aish recently lol

Also I've been greeting the old Korean Couple who runs a sandwich shop that I go to on occasion with "Annyeong haseo" haha

헐 "heol" which is a slang word and can translate to "what the hell/oh my god"
잘 먹겠습니다 "jal meokgesseumnida" translated to "thanks for the meal/thank you for dinner" it's just like bon appetit but backwards.
깜짝이야 "kkamjjakiya" basically means "you scared me/you startled me"

I use "omo" and "aigoo" a lot which can be a bit weird since I live in an area with a decent-sized Korean community.

:)

I really love korean language. I've been watching kdramas and I can understand few common words. My goal is to watch kdrama without subtitles but I don't know when it will happen. :D
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Few words from my memory:
Aigoooo (I say this even when I yawn lol), Aishhh, Jincha, Omo, Ottoke, Hyung, Noona, Unni, Ajjumma, Yaaah!, Komawo, Annyong, Bianheyo, Kamsahamnida, Shiro, igo boya/mwoya (I've heard this frequently in return of the superman. Curious kids used to say this frequently) , Nae sarang (especially in benteley's tone), wae, andwae, saranghae,
nomu nomu, palli, gatchi mogcha, jugulle, hajima, pogoshipta, mashinnae, daebak, molla, yennal yennal, kyowoo, yeppuda, oppaaaa (especially in Yo Na's tone) :)

I like Korean gestures too.  Like the one for confrontation, where someone leans in over another person's shoulder and talks frankly to them.  Getting in their face without getting in their face.  At least, that is how I see it.