Aigoo and omo. I use both of those in my personal life. 
Ya! It's short and concise and so much more satisfying than "hey" :)
ddong sounds so funny to me...
I think it's so funny to hear them saying "Mwo???" (it's also funny in japanese "nani???") 
hajima
bichoso
bogoshipoyo
yoboseyo
huegure
wae?


ps: I just spell how it sounds like. lol
i love "Ghopjoggei wae?!" or simply "ghopjoggie!" for use when someone startles you.

literal translation is "suddenly, why?"  or "suddenly!" for use when someone startles you.

Ghoppjoggi wae, when yelled, always sounds like "WTF are you doing?!" 
I love saying HEOOOLLLLL....  xD
꺼져 kkeojyeo - "Get Lost" I say this everyday. It's gotten so bad that my mom started saying it to me when I annoy her.
나가  naga - "Get Out" .
미쳤어 michyeoss-eo - "Are you crazy"
Anyone seeing the patter here lol

Daebak
, you can use it everywhere
Oppa and arrasso( i keep using these two words)
Andwae and Chincha! I am always uttering that to everyone I'm talking to. haha!
I call my husband Yeobo, I have 2 boys so I call them Adeuls, I use Pali Pali a lot, told my brother to call me Noona, I greet my family with Annyeonghaseyo, I also use Omo, Aish, Saranghae, arasso, and a few others.

My family has accepted that I think I'm Asian and just go along with me. :)
I have the habit of saying Arasseo to everybody, and when I mistakenly said it to my teacher & my teacher just laughed at me hahhaha . And like literally I always use that instead of saying OKAY ^_^