I'm using "aigoo", "aish", "ya!" and "omo" everyday now.
짜잔 ~ (jjajan ~)
바보 (babo)
진짜 (jinjja)
정말 (jeongmal)
알았어 (arasseo)
괜찮아 (gwenchana)
사랑해 (saranghae)
미안해 (mianhae)
가자 (kaja)
빨리 (ppalli)
잠깐만 (jamkkanman)
보고싶어 (bogosipeo)
죽을래 (jugeullae)
오빠 (oppa)
그래 (geurae)
싫어 (shiro) - "I don't like it" or something along that line.
아파요 (apayo) - "It hurts."
친구 (chingu) - "friend"
맛있다 (masissda) - Pronounced as mah-shi-tah. Became my favorite because of Miho in MGIAG. :))
가지마 (gajima) - I really, really, really loved this word because of Song Joong Ki. kekeke
대박 (daebak) - I use this a lot, especially when fangirling over K-idols. HAHAHA
배고파 (baegopa) - "I'm hungry". 'Cause, yeah, I love food. :))
(너) 미쳤어? [(neo) michyeosseo] - "Are you crazy?" I love using this. XD
심심해 (simsimhae) - Pronounced as "shimshimhae". It means "I'm bored". :>
걱정마 (geokjeongma) - "Don't worry."
말도 안돼 (maldo andwae) - "No way!", "Impossible!", or something along those lines. XD
됐어 (dwaesseo) - "It's okay" or "Forget it". Depends on how one said it.
난 널 좋아해 (nan neol johahae) - "I like you."
무슨 말이야 (museun mariya) - "What do you mean?"
왜그래 (waegeurae) - "Why are you being like this?"
선생님 (seonsaengnim) - I really love the sound of this.
약속 (yaksok) - "promise"
들어 봐요 (deuleo boayo) - "Listen."
Yep. I love a lot of Korean words. <3